50 files changed, 895 insertions, 132 deletions
diff --git a/CHANGES b/CHANGES
index 5d686d3..7dd03c4 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,51 @@
+2023-02-08 Jerry Lundström
+
+    Release 2.11.0
+
+    A couple of new features this release courtesy of Petr Špaček
+    @pspacek (ISC) and a bunch of bugfixes.
+
+    First off `dnsperf` can now do verbose statistics during each interval
+    when using `-S`, see long option `verbose-interval-stats`.
+
+    Next is a new latency histogram output using data structures (hg64)
+    created by Tony Finch @fanf2 (ISC), see long option
+    `latency-histogram`. These will also be shown during `-S` when used
+    together with `verbose-interval-stats`.
+
+    Lastly a small change to boolean long options, they no longer require
+    a value (`=yes`) to be enabled.
+
+    Bugfixes:
+    - Make sure the number of outstanding queries don't go negative,
+      happens if queries are timed out before being sent
+    - Fixed #208:
+      - `recv_one()`: Fix handling errno, only store EAGAIN if no other
+        error has been received
+      - `do_recv()`: Don't break on error as it will count it as a received
+        message
+      - Treat `EBADF` as `EAGAIN` for stateful connections, receive thread
+        might read from a closed socket if send thread is reconnecting
+    - `dnsperf`: warn if -c, -T, -q, -Q values are auto-adjusted
+    - Fixed #222: don't process unexpected message if the message is
+      suppressed
+
+    14db835 Opt arg
+    fb81481 Suppress unexpected
+    64b8c6d stats_t initialization
+    8290775 Fix first call to diff_stats
+    4f8bd24 Compile support histograms
+    a9b4f04 External code, latency histograms
+    d1f4b65 add detailed latency histograms
+    044e3a2 data structures for detailed latency histograms
+    ad3fb03 Opt, verbose statistics
+    38bc936 Command usage warnings
+    9f31595 Bad file descriptor
+    d3650eb Receive socket error handling
+    84c8e72 Negative outstanding
+    e7df5e1 Clarify meaning of dnsperf -S output in the man page
+    830eb43 verbose interval stats for dnsperf
+
 2022-11-11 Jerry Lundström
 
     Release 2.10.0
diff --git a/Makefile.am b/Makefile.am
index a992b0e..594735c 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,4 +1,4 @@
-# Copyright 2019-2022 OARC, Inc.
+# Copyright 2019-2023 OARC, Inc.
 # Copyright 2017-2018 Akamai Technologies
 # Copyright 2006-2016 Nominum, Inc.
 # All rights reserved.
diff --git a/Makefile.in b/Makefile.in
index 1fe1047..945d94a 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -14,7 +14,7 @@
 
 @SET_MAKE@
 
-# Copyright 2019-2022 OARC, Inc.
+# Copyright 2019-2023 OARC, Inc.
 # Copyright 2017-2018 Akamai Technologies
 # Copyright 2006-2016 Nominum, Inc.
 # All rights reserved.
diff --git a/README.md b/README.md
index 123c7a5..5ddb412 100644
--- a/README.md
+++ b/README.md
@@ -100,7 +100,7 @@ The contrib directory contains additional software related to `dnsperf` and
 ## License
 
 ```
-Copyright 2019-2022 OARC, Inc.
+Copyright 2019-2023 OARC, Inc.
 Copyright 2017-2018 Akamai Technologies
 Copyright 2006-2016 Nominum, Inc.
 All rights reserved.
diff --git a/configure b/configure
index de90675..91c1516 100755
--- a/configure
+++ b/configure
@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for dnsperf 2.10.0.
+# Generated by GNU Autoconf 2.69 for dnsperf 2.11.0.
 #
 # Report bugs to <admin@dns-oarc.net>.
 #
@@ -590,8 +590,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='dnsperf'
 PACKAGE_TARNAME='dnsperf'
-PACKAGE_VERSION='2.10.0'
-PACKAGE_STRING='dnsperf 2.10.0'
+PACKAGE_VERSION='2.11.0'
+PACKAGE_STRING='dnsperf 2.11.0'
 PACKAGE_BUGREPORT='admin@dns-oarc.net'
 PACKAGE_URL='https://github.com/DNS-OARC/dnsperf/issues'
 
@@ -649,6 +649,8 @@ libssl_CFLAGS
 PKG_CONFIG_LIBDIR
 PKG_CONFIG_PATH
 PKG_CONFIG
+HAVE_STDATOMIC_FALSE
+HAVE_STDATOMIC_TRUE
 PTHREAD_CFLAGS
 PTHREAD_LIBS
 PTHREAD_CC
@@ -1360,7 +1362,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures dnsperf 2.10.0 to adapt to many kinds of systems.
+\`configure' configures dnsperf 2.11.0 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1431,7 +1433,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of dnsperf 2.10.0:";;
+     short | recursive ) echo "Configuration of dnsperf 2.11.0:";;
    esac
   cat <<\_ACEOF
 
@@ -1570,7 +1572,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-dnsperf configure 2.10.0
+dnsperf configure 2.11.0
 generated by GNU Autoconf 2.69
 
 Copyright (C) 2012 Free Software Foundation, Inc.
@@ -1939,7 +1941,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by dnsperf $as_me 2.10.0, which was
+It was created by dnsperf $as_me 2.11.0, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   $ $0 $@
@@ -2802,7 +2804,7 @@ fi
 
 # Define the identity of the package.
  PACKAGE='dnsperf'
- VERSION='2.10.0'
+ VERSION='2.11.0'
 
 
 cat >>confdefs.h <<_ACEOF
@@ -12891,6 +12893,26 @@ _ACEOF
 
 fi
 
+for ac_header in stdatomic.h
+do :
+  ac_fn_c_check_header_mongrel "$LINENO" "stdatomic.h" "ac_cv_header_stdatomic_h" "$ac_includes_default"
+if test "x$ac_cv_header_stdatomic_h" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_STDATOMIC_H 1
+_ACEOF
+
+fi
+
+done
+
+ if test "x$ac_cv_header_stdatomic_h" != "xno"; then
+  HAVE_STDATOMIC_TRUE=
+  HAVE_STDATOMIC_FALSE='#'
+else
+  HAVE_STDATOMIC_TRUE='#'
+  HAVE_STDATOMIC_FALSE=
+fi
+
 
 # Check for OpenSSL
 
@@ -14013,6 +14035,10 @@ if test -z "${ENABLE_GCOV_TRUE}" && test -z "${ENABLE_GCOV_FALSE}"; then
   as_fn_error $? "conditional \"ENABLE_GCOV\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
 fi
+if test -z "${HAVE_STDATOMIC_TRUE}" && test -z "${HAVE_STDATOMIC_FALSE}"; then
+  as_fn_error $? "conditional \"HAVE_STDATOMIC\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
 
 : "${CONFIG_STATUS=./config.status}"
 ac_write_fail=0
@@ -14410,7 +14436,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by dnsperf $as_me 2.10.0, which was
+This file was extended by dnsperf $as_me 2.11.0, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -14477,7 +14503,7 @@ _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
 ac_cs_version="\\
-dnsperf config.status 2.10.0
+dnsperf config.status 2.11.0
 configured by $0, generated by GNU Autoconf 2.69,
   with options \\"\$ac_cs_config\\"
 
diff --git a/configure.ac b/configure.ac
index 0a0130b..fa664da 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,4 @@
-# Copyright 2019-2022 OARC, Inc.
+# Copyright 2019-2023 OARC, Inc.
 # Copyright 2017-2018 Akamai Technologies
 # Copyright 2006-2016 Nominum, Inc.
 # All rights reserved.
@@ -16,7 +16,7 @@
 # limitations under the License.
 
 AC_PREREQ(2.64)
-AC_INIT([dnsperf], [2.10.0], [admin@dns-oarc.net], [dnsperf], [https://github.com/DNS-OARC/dnsperf/issues])
+AC_INIT([dnsperf], [2.11.0], [admin@dns-oarc.net], [dnsperf], [https://github.com/DNS-OARC/dnsperf/issues])
 AM_INIT_AUTOMAKE([-Wall -Werror foreign subdir-objects])
 AC_CONFIG_SRCDIR([src/dnsperf.c])
 AC_CONFIG_HEADER([src/config.h])
@@ -56,6 +56,8 @@ AM_EXTRA_RECURSIVE_TARGETS([gcov])
 # Checks for support.
 AX_PTHREAD
 AC_CHECK_LIB([m], [sqrt])
+AC_CHECK_HEADERS([stdatomic.h])
+AM_CONDITIONAL([HAVE_STDATOMIC], [test "x$ac_cv_header_stdatomic_h" != "xno"])
 
 # Check for OpenSSL
 PKG_CHECK_MODULES([libssl], [libssl])
diff --git a/contrib/queryparse/queryparse b/contrib/queryparse/queryparse
index b138406..8e12108 100755
--- a/contrib/queryparse/queryparse
+++ b/contrib/queryparse/queryparse
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 #
-# Copyright 2019-2022 OARC, Inc.
+# Copyright 2019-2023 OARC, Inc.
 # Copyright 2017-2018 Akamai Technologies
 # Copyright 2006-2016 Nominum, Inc.
 # All rights reserved.
diff --git a/contrib/queryparse/queryparse.1 b/contrib/queryparse/queryparse.1
index 3483d27..36c14cb 100644
--- a/contrib/queryparse/queryparse.1
+++ b/contrib/queryparse/queryparse.1
@@ -1,4 +1,4 @@
-.\" Copyright 2019-2022 OARC, Inc.
+.\" Copyright 2019-2023 OARC, Inc.
 .\" Copyright 2017-2018 Akamai Technologies
 .\" Copyright 2006-2016 Nominum, Inc.
 .\" All rights reserved.
diff --git a/m4/dnsperf.m4 b/m4/dnsperf.m4
index fb5378d..4cf228f 100644
--- a/m4/dnsperf.m4
+++ b/m4/dnsperf.m4
@@ -1,4 +1,4 @@
-# Copyright 2019-2022 OARC, Inc.
+# Copyright 2019-2023 OARC, Inc.
 # Copyright 2017-2018 Akamai Technologies
 # Copyright 2006-2016 Nominum, Inc.
 # All rights reserved.
diff --git a/src/Makefile.am b/src/Makefile.am
index 119e187..810f99b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,4 +1,4 @@
-# Copyright 2019-2022 OARC, Inc.
+# Copyright 2019-2023 OARC, Inc.
 # Copyright 2017-2018 Akamai Technologies
 # Copyright 2006-2016 Nominum, Inc.
 # All rights reserved.
@@ -30,9 +30,15 @@ bin_PROGRAMS = dnsperf resperf
 dist_bin_SCRIPTS = resperf-report
 
 _libperf_sources = datafile.c dns.c log.c net.c opt.c os.c strerror.c qtype.c \
-  edns.c tsig.c net_udp.c net_tcp.c net_dot.c net_doh.c parse_uri.c
+  edns.c tsig.c net_udp.c net_tcp.c net_dot.c net_doh.c ext/parse_uri.c
+
 _libperf_headers = datafile.h dns.h log.h net.h opt.h os.h util.h strerror.h \
-  list.h result.h buffer.h qtype.h edns.h tsig.h parse_uri.h
+  list.h result.h buffer.h qtype.h edns.h tsig.h ext/parse_uri.h
+
+if HAVE_STDATOMIC
+_libperf_sources += ext/hg64.c
+_libperf_headers += ext/hg64.h
+endif
 
 dnsperf_SOURCES = $(_libperf_sources) dnsperf.c
 dist_dnsperf_SOURCES = $(_libperf_headers)
diff --git a/src/Makefile.in b/src/Makefile.in
index 1772980..1b510c7 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -14,7 +14,7 @@
 
 @SET_MAKE@
 
-# Copyright 2019-2022 OARC, Inc.
+# Copyright 2019-2023 OARC, Inc.
 # Copyright 2017-2018 Akamai Technologies
 # Copyright 2006-2016 Nominum, Inc.
 # All rights reserved.
@@ -107,6 +107,8 @@ POST_UNINSTALL = :
 build_triplet = @build@
 host_triplet = @host@
 bin_PROGRAMS = dnsperf$(EXEEXT) resperf$(EXEEXT)
+@HAVE_STDATOMIC_TRUE@am__append_1 = ext/hg64.c
+@HAVE_STDATOMIC_TRUE@am__append_2 = ext/hg64.h
 subdir = src
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/ax_append_flag.m4 \
@@ -127,14 +129,23 @@ CONFIG_CLEAN_VPATH_FILES =
 am__installdirs = "$(DESTDIR)$(bindir)" "$(DESTDIR)$(bindir)" \
 	"$(DESTDIR)$(man1dir)"
 PROGRAMS = $(bin_PROGRAMS)
-am__objects_1 = datafile.$(OBJEXT) dns.$(OBJEXT) log.$(OBJEXT) \
+am__dnsperf_SOURCES_DIST = datafile.c dns.c log.c net.c opt.c os.c \
+	strerror.c qtype.c edns.c tsig.c net_udp.c net_tcp.c net_dot.c \
+	net_doh.c ext/parse_uri.c ext/hg64.c dnsperf.c
+am__dirstamp = $(am__leading_dot)dirstamp
+@HAVE_STDATOMIC_TRUE@am__objects_1 = ext/hg64.$(OBJEXT)
+am__objects_2 = datafile.$(OBJEXT) dns.$(OBJEXT) log.$(OBJEXT) \
 	net.$(OBJEXT) opt.$(OBJEXT) os.$(OBJEXT) strerror.$(OBJEXT) \
 	qtype.$(OBJEXT) edns.$(OBJEXT) tsig.$(OBJEXT) \
 	net_udp.$(OBJEXT) net_tcp.$(OBJEXT) net_dot.$(OBJEXT) \
-	net_doh.$(OBJEXT) parse_uri.$(OBJEXT)
-am_dnsperf_OBJECTS = $(am__objects_1) dnsperf.$(OBJEXT)
-am__objects_2 =
-dist_dnsperf_OBJECTS = $(am__objects_2)
+	net_doh.$(OBJEXT) ext/parse_uri.$(OBJEXT) $(am__objects_1)
+am_dnsperf_OBJECTS = $(am__objects_2) dnsperf.$(OBJEXT)
+am__dist_dnsperf_SOURCES_DIST = datafile.h dns.h log.h net.h opt.h \
+	os.h util.h strerror.h list.h result.h buffer.h qtype.h edns.h \
+	tsig.h ext/parse_uri.h ext/hg64.h
+am__objects_3 =
+am__objects_4 = $(am__objects_3)
+dist_dnsperf_OBJECTS = $(am__objects_4)
 dnsperf_OBJECTS = $(am_dnsperf_OBJECTS) $(dist_dnsperf_OBJECTS)
 am__DEPENDENCIES_1 =
 dnsperf_DEPENDENCIES = $(am__DEPENDENCIES_1) $(am__DEPENDENCIES_1) \
@@ -144,8 +155,14 @@ AM_V_lt = $(am__v_lt_@AM_V@)
 am__v_lt_ = $(am__v_lt_@AM_DEFAULT_V@)
 am__v_lt_0 = --silent
 am__v_lt_1 = 
-am_resperf_OBJECTS = $(am__objects_1) resperf.$(OBJEXT)
-dist_resperf_OBJECTS = $(am__objects_2)
+am__resperf_SOURCES_DIST = datafile.c dns.c log.c net.c opt.c os.c \
+	strerror.c qtype.c edns.c tsig.c net_udp.c net_tcp.c net_dot.c \
+	net_doh.c ext/parse_uri.c ext/hg64.c resperf.c
+am_resperf_OBJECTS = $(am__objects_2) resperf.$(OBJEXT)
+am__dist_resperf_SOURCES_DIST = datafile.h dns.h log.h net.h opt.h \
+	os.h util.h strerror.h list.h result.h buffer.h qtype.h edns.h \
+	tsig.h ext/parse_uri.h ext/hg64.h
+dist_resperf_OBJECTS = $(am__objects_4)
 resperf_OBJECTS = $(am_resperf_OBJECTS) $(dist_resperf_OBJECTS)
 resperf_DEPENDENCIES = $(am__DEPENDENCIES_1) $(am__DEPENDENCIES_1) \
 	$(am__DEPENDENCIES_1) $(am__DEPENDENCIES_1) \
@@ -198,9 +215,9 @@ am__depfiles_remade = ./$(DEPDIR)/datafile.Po ./$(DEPDIR)/dns.Po \
 	./$(DEPDIR)/net.Po ./$(DEPDIR)/net_doh.Po \
 	./$(DEPDIR)/net_dot.Po ./$(DEPDIR)/net_tcp.Po \
 	./$(DEPDIR)/net_udp.Po ./$(DEPDIR)/opt.Po ./$(DEPDIR)/os.Po \
-	./$(DEPDIR)/parse_uri.Po ./$(DEPDIR)/qtype.Po \
-	./$(DEPDIR)/resperf.Po ./$(DEPDIR)/strerror.Po \
-	./$(DEPDIR)/tsig.Po
+	./$(DEPDIR)/qtype.Po ./$(DEPDIR)/resperf.Po \
+	./$(DEPDIR)/strerror.Po ./$(DEPDIR)/tsig.Po \
+	ext/$(DEPDIR)/hg64.Po ext/$(DEPDIR)/parse_uri.Po
 am__mv = mv -f
 COMPILE = $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) \
 	$(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS)
@@ -222,8 +239,9 @@ am__v_CCLD_0 = @echo "  CCLD    " $@;
 am__v_CCLD_1 = 
 SOURCES = $(dnsperf_SOURCES) $(dist_dnsperf_SOURCES) \
 	$(resperf_SOURCES) $(dist_resperf_SOURCES)
-DIST_SOURCES = $(dnsperf_SOURCES) $(dist_dnsperf_SOURCES) \
-	$(resperf_SOURCES) $(dist_resperf_SOURCES)
+DIST_SOURCES = $(am__dnsperf_SOURCES_DIST) \
+	$(am__dist_dnsperf_SOURCES_DIST) $(am__resperf_SOURCES_DIST) \
+	$(am__dist_resperf_SOURCES_DIST)
 RECURSIVE_TARGETS = all-recursive check-recursive cscopelist-recursive \
 	ctags-recursive dvi-recursive html-recursive info-recursive \
 	install-data-recursive install-dvi-recursive \
@@ -440,12 +458,12 @@ AM_CFLAGS = -I$(srcdir) \
 
 EXTRA_DIST = dnsperf.1.in resperf-report resperf.1.in
 dist_bin_SCRIPTS = resperf-report
-_libperf_sources = datafile.c dns.c log.c net.c opt.c os.c strerror.c qtype.c \
-  edns.c tsig.c net_udp.c net_tcp.c net_dot.c net_doh.c parse_uri.c
-
-_libperf_headers = datafile.h dns.h log.h net.h opt.h os.h util.h strerror.h \
-  list.h result.h buffer.h qtype.h edns.h tsig.h parse_uri.h
-
+_libperf_sources = datafile.c dns.c log.c net.c opt.c os.c strerror.c \
+	qtype.c edns.c tsig.c net_udp.c net_tcp.c net_dot.c net_doh.c \
+	ext/parse_uri.c $(am__append_1)
+_libperf_headers = datafile.h dns.h log.h net.h opt.h os.h util.h \
+	strerror.h list.h result.h buffer.h qtype.h edns.h tsig.h \
+	ext/parse_uri.h $(am__append_2)
 dnsperf_SOURCES = $(_libperf_sources) dnsperf.c
 dist_dnsperf_SOURCES = $(_libperf_headers)
 dnsperf_LDADD = $(PTHREAD_LIBS) $(libssl_LIBS) $(libcrypto_LIBS) \
@@ -555,6 +573,15 @@ clean-binPROGRAMS:
 	list=`for p in $$list; do echo "$$p"; done | sed 's/$(EXEEXT)$$//'`; \
 	echo " rm -f" $$list; \
 	rm -f $$list
+ext/$(am__dirstamp):
+	@$(MKDIR_P) ext
+	@: > ext/$(am__dirstamp)
+ext/$(DEPDIR)/$(am__dirstamp):
+	@$(MKDIR_P) ext/$(DEPDIR)
+	@: > ext/$(DEPDIR)/$(am__dirstamp)
+ext/parse_uri.$(OBJEXT): ext/$(am__dirstamp) \
+	ext/$(DEPDIR)/$(am__dirstamp)
+ext/hg64.$(OBJEXT): ext/$(am__dirstamp) ext/$(DEPDIR)/$(am__dirstamp)
 
 dnsperf$(EXEEXT): $(dnsperf_OBJECTS) $(dnsperf_DEPENDENCIES) $(EXTRA_dnsperf_DEPENDENCIES) 
 	@rm -f dnsperf$(EXEEXT)
@@ -601,6 +628,7 @@ uninstall-dist_binSCRIPTS:
 
 mostlyclean-compile:
 	-rm -f *.$(OBJEXT)
+	-rm -f ext/*.$(OBJEXT)
 
 distclean-compile:
 	-rm -f *.tab.c
@@ -617,11 +645,12 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/net_udp.Po@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/opt.Po@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/os.Po@am__quote@ # am--include-marker
-@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/parse_uri.Po@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/qtype.Po@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/resperf.Po@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/strerror.Po@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/tsig.Po@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@ext/$(DEPDIR)/hg64.Po@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@ext/$(DEPDIR)/parse_uri.Po@am__quote@ # am--include-marker
 
 $(am__depfiles_remade):
 	@$(MKDIR_P) $(@D)
@@ -893,6 +922,8 @@ clean-generic:
 distclean-generic:
 	-test -z "$(CONFIG_CLEAN_FILES)" || rm -f $(CONFIG_CLEAN_FILES)
 	-test . = "$(srcdir)" || test -z "$(CONFIG_CLEAN_VPATH_FILES)" || rm -f $(CONFIG_CLEAN_VPATH_FILES)
+	-rm -f ext/$(DEPDIR)/$(am__dirstamp)
+	-rm -f ext/$(am__dirstamp)
 
 maintainer-clean-generic:
 	@echo "This command is intended for maintainers to use"
@@ -916,11 +947,12 @@ distclean: distclean-recursive
 	-rm -f ./$(DEPDIR)/net_udp.Po
 	-rm -f ./$(DEPDIR)/opt.Po
 	-rm -f ./$(DEPDIR)/os.Po
-	-rm -f ./$(DEPDIR)/parse_uri.Po
 	-rm -f ./$(DEPDIR)/qtype.Po
 	-rm -f ./$(DEPDIR)/resperf.Po
 	-rm -f ./$(DEPDIR)/strerror.Po
 	-rm -f ./$(DEPDIR)/tsig.Po
+	-rm -f ext/$(DEPDIR)/hg64.Po
+	-rm -f ext/$(DEPDIR)/parse_uri.Po
 	-rm -f Makefile
 distclean-am: clean-am distclean-compile distclean-generic \
 	distclean-hdr distclean-tags
@@ -982,11 +1014,12 @@ maintainer-clean: maintainer-clean-recursive
 	-rm -f ./$(DEPDIR)/net_udp.Po
 	-rm -f ./$(DEPDIR)/opt.Po
 	-rm -f ./$(DEPDIR)/os.Po
-	-rm -f ./$(DEPDIR)/parse_uri.Po
 	-rm -f ./$(DEPDIR)/qtype.Po
 	-rm -f ./$(DEPDIR)/resperf.Po
 	-rm -f ./$(DEPDIR)/strerror.Po
 	-rm -f ./$(DEPDIR)/tsig.Po
+	-rm -f ext/$(DEPDIR)/hg64.Po
+	-rm -f ext/$(DEPDIR)/parse_uri.Po
 	-rm -f Makefile
 maintainer-clean-am: distclean-am maintainer-clean-generic
 
diff --git a/src/buffer.h b/src/buffer.h
index 52bfef2..1cc5962 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/config.h.in b/src/config.h.in
index 49e5f44..bdd273f 100644
--- a/src/config.h.in
+++ b/src/config.h.in
@@ -36,6 +36,9 @@
 /* Have PTHREAD_PRIO_INHERIT. */
 #undef HAVE_PTHREAD_PRIO_INHERIT
 
+/* Define to 1 if you have the <stdatomic.h> header file. */
+#undef HAVE_STDATOMIC_H
+
 /* Define to 1 if you have the <stdint.h> header file. */
 #undef HAVE_STDINT_H
 
diff --git a/src/datafile.c b/src/datafile.c
index 06ea0ea..85e34b8 100644
--- a/src/datafile.c
+++ b/src/datafile.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/datafile.h b/src/datafile.h
index a1b737e..bebc1e9 100644
--- a/src/datafile.h
+++ b/src/datafile.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/dns.c b/src/dns.c
index 20bb354..c990d9b 100644
--- a/src/dns.c
+++ b/src/dns.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/dns.h b/src/dns.h
index c126f97..0c0df3c 100644
--- a/src/dns.h
+++ b/src/dns.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/dnsperf.1.in b/src/dnsperf.1.in
index 9ae24bd..c44a5f3 100644
--- a/src/dnsperf.1.in
+++ b/src/dnsperf.1.in
@@ -1,4 +1,4 @@
-.\" Copyright 2019-2022 OARC, Inc.
+.\" Copyright 2019-2023 OARC, Inc.
 .\" Copyright 2017-2018 Akamai Technologies
 .\" Copyright 2006-2016 Nominum, Inc.
 .\" All rights reserved.
@@ -341,8 +341,9 @@ The default is the loopback address, 127.0.0.1.
 \fB-S \fIstats_interval\fR
 .br
 .RS
-If this parameter is specified, a count of the number of queries per second
-during the interval will be printed out every stats_interval seconds.
+If this parameter is specified, a count of the number of answers received
+per second during the interval will be printed out every \fIstats_interval\fR
+seconds.
 .RE
 
 \fB-t \fItimeout\fR
@@ -458,7 +459,6 @@ Following type are available.
 .br
 \fBunexpected\fR: Suppress messages about answers with an unexpected message ID
 .RE
-
 \fBnum-queries-per-conn=\fINUMBER\fR
 .br
 .RS
@@ -474,6 +474,29 @@ Waiting for responses may timeout and the timeout used for this is the
 same as specified by \fB-t\fR.
 Note that this option is only useful for connection oriented protocols.
 .RE
+
+\fBverbose-interval-stats\fR
+.br
+.RS
+Change the statistics format of \fB-S\fR to that shown at end of run.
+
+\fIPlease note\fR: Min/max values for latency and connections are not
+available in interval statistics.
+Number of answers received within \fIstats_interval\fR can legitimately
+exceed number of queries sent, depending on answer latency, configured
+\fItimeout\fR, and \fIstats_interval\fR.
+.RE
+
+\fBlatency-histogram\fR
+.br
+.RS
+Print detailed latency histograms for DNS answers and connections.
+Latency is quantized into bins with roughly 3 % resolution, and latency
+range for individual bins increases logarithmically.
+This is done to to limit amount of memory required for histograms
+and also allows to visualize latency using logarithmic percentile histograms
+with minimal postprocessing.
+.RE
 .SH "SEE ALSO"
 \fBresperf\fR(1)
 .SH AUTHOR
diff --git a/src/dnsperf.c b/src/dnsperf.c
index 7d10212..90b7874 100644
--- a/src/dnsperf.c
+++ b/src/dnsperf.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
@@ -32,6 +32,10 @@
 #include "util.h"
 #include "list.h"
 #include "buffer.h"
+#if HAVE_STDATOMIC_H
+#include "ext/hg64.h"
+#define USE_HISTOGRAMS
+#endif
 
 #include <inttypes.h>
 #include <errno.h>
@@ -49,6 +53,8 @@
 #include <openssl/conf.h>
 #include <openssl/err.h>
 
+#define HISTOGRAM_SIGBITS 5 /* about 3 % latency precision */
+
 #define DEFAULT_SERVER_NAME "127.0.0.1"
 #define DEFAULT_SERVER_PORT 53
 #define DEFAULT_SERVER_DOT_PORT 853
@@ -85,6 +91,7 @@ typedef struct {
     uint32_t            max_outstanding;
     uint32_t            max_qps;
     uint64_t            stats_interval;
+    bool                verbose_interval_stats;
     bool                updates;
     bool                binary_input;
     perf_input_format_t input_format;
@@ -92,6 +99,9 @@ typedef struct {
     enum perf_net_mode  mode;
     perf_suppress_t     suppress;
     size_t              num_queries_per_conn;
+#ifdef USE_HISTOGRAMS
+    bool latency_histogram;
+#endif
 } config_t;
 
 typedef struct {
@@ -101,8 +111,9 @@ typedef struct {
     struct timespec stop_time_ns;
 } times_t;
 
+#define DNSPERF_STATS_RCODECOUNTS 16
 typedef struct {
-    uint64_t rcodecounts[16];
+    uint64_t rcodecounts[DNSPERF_STATS_RCODECOUNTS];
 
     uint64_t num_sent;
     uint64_t num_interrupted;
@@ -124,6 +135,11 @@ typedef struct {
     uint64_t conn_latency_sum_squares;
     uint64_t conn_latency_min;
     uint64_t conn_latency_max;
+
+#ifdef USE_HISTOGRAMS
+    hg64* latency;
+    hg64* conn_latency;
+#endif
 } stats_t;
 
 typedef perf_list(struct query_info) query_list;
@@ -257,7 +273,86 @@ stddev(uint64_t sum_of_squares, uint64_t sum, uint64_t total)
 }
 
 static void
-print_statistics(const config_t* config, const times_t* times, stats_t* stats)
+diff_stats(const config_t* config, stats_t* last, stats_t* now, stats_t* diff)
+{
+    int i = 0;
+    for (; i < DNSPERF_STATS_RCODECOUNTS; i++) {
+        diff->rcodecounts[i] = now->rcodecounts[i] - last->rcodecounts[i];
+    }
+
+    diff->num_sent        = now->num_sent - last->num_sent;
+    diff->num_interrupted = now->num_interrupted - last->num_interrupted;
+    diff->num_timedout    = now->num_timedout - last->num_timedout;
+    diff->num_completed   = now->num_completed - last->num_completed;
+
+    diff->total_request_size  = now->total_request_size - last->total_request_size;
+    diff->total_response_size = now->total_response_size - last->total_response_size;
+
+    diff->latency_sum         = now->latency_sum - last->latency_sum;
+    diff->latency_sum_squares = now->latency_sum_squares - last->latency_sum_squares;
+    diff->latency_min         = 0; /* not enough data */
+    diff->latency_max         = 0;
+
+    diff->num_conn_reconnect = now->num_conn_reconnect - last->num_conn_reconnect;
+    diff->num_conn_completed = now->num_conn_completed - last->num_conn_completed;
+
+    diff->conn_latency_sum         = now->conn_latency_sum - last->conn_latency_sum;
+    diff->conn_latency_sum_squares = now->conn_latency_sum_squares - last->conn_latency_sum_squares;
+    diff->conn_latency_min         = 0;
+    diff->conn_latency_max         = 0;
+
+#ifdef USE_HISTOGRAMS
+    if (config->latency_histogram) {
+        free(diff->latency);
+        diff->latency = hg64_create(HISTOGRAM_SIGBITS);
+        if (last->latency) {
+            hg64_diff(now->latency, last->latency, diff->latency);
+        } else { /* first sample */
+            hg64_merge(diff->latency, now->latency);
+        }
+        hg64_get(diff->latency, hg64_min_key(diff->latency), &diff->latency_min, NULL, NULL);
+        hg64_get(diff->latency, hg64_max_key(diff->latency), NULL, &diff->latency_max, NULL);
+
+        free(diff->conn_latency);
+        diff->conn_latency = hg64_create(HISTOGRAM_SIGBITS);
+        if (last->conn_latency) {
+            hg64_diff(now->conn_latency, last->conn_latency, diff->conn_latency);
+        } else { /* first sample */
+            hg64_merge(diff->conn_latency, now->conn_latency);
+        }
+        hg64_get(diff->conn_latency, hg64_min_key(diff->conn_latency), &diff->conn_latency_min, NULL, NULL);
+        hg64_get(diff->conn_latency, hg64_max_key(diff->conn_latency), NULL, &diff->conn_latency_max, NULL);
+    }
+#endif
+}
+
+#ifdef USE_HISTOGRAMS
+static void
+print_histogram(hg64* histogram, const char* const desc)
+{
+    printf("  Latency bucket (s):   %s\n", desc);
+    uint64_t pmin, pmax, pcount;
+    for (unsigned key = 0;
+         hg64_get(histogram, key, &pmin, &pmax, &pcount) == true;
+         key = hg64_next(histogram, key)) {
+        if (pcount == 0)
+            continue;
+        printf("  %" PRIu64 ".%06" PRIu64 " - %" PRIu64 ".%06" PRIu64 ":  %" PRIu64 "\n",
+            pmin / MILLION,
+            pmin % MILLION,
+            pmax / MILLION,
+            pmax % MILLION,
+            pcount);
+    };
+}
+#endif
+
+/*
+ * now != 0 is call to print stats in the middle of test run.
+ * min-max values are not available on per-interval basis, so skip them.
+ */
+static void
+print_statistics(const config_t* config, const times_t* times, stats_t* stats, uint64_t now, uint64_t interval_time)
 {
     const char*  units;
     uint64_t     run_time;
@@ -267,9 +362,12 @@ print_statistics(const config_t* config, const times_t* times, stats_t* stats)
 
     units = config->updates ? "Updates" : "Queries";
 
-    run_time = times->end_time - times->start_time;
+    if (now)
+        run_time = now - times->start_time;
+    else
+        run_time = times->end_time - times->start_time;
 
-    printf("Statistics:\n\n");
+    printf("%sStatistics:\n\n", now ? "Interval " : "");
 
     printf("  %s sent:         %" PRIu64 "\n",
         units, stats->num_sent);
@@ -287,7 +385,7 @@ print_statistics(const config_t* config, const times_t* times, stats_t* stats)
 
     printf("  Response codes:       ");
     first_rcode = true;
-    for (i = 0; i < 16; i++) {
+    for (i = 0; i < DNSPERF_STATS_RCODECOUNTS; i++) {
         if (stats->rcodecounts[i] == 0)
             continue;
         if (first_rcode)
@@ -308,23 +406,33 @@ print_statistics(const config_t* config, const times_t* times, stats_t* stats)
         (unsigned int)(run_time / MILLION),
         (unsigned int)(run_time % MILLION));
     printf("  %s per second:   %.6lf\n", units,
-        PERF_SAFE_DIV(stats->num_completed, (((double)run_time) / MILLION)));
+        PERF_SAFE_DIV(stats->num_completed, (((double)(now ? interval_time : run_time) / MILLION))));
 
     printf("\n");
 
     latency_avg = PERF_SAFE_DIV(stats->latency_sum, stats->num_completed);
-    printf("  Average Latency (s):  %u.%06u (min %u.%06u, max %u.%06u)\n",
+    printf("  Average Latency (s):  %u.%06u",
         (unsigned int)(latency_avg / MILLION),
-        (unsigned int)(latency_avg % MILLION),
-        (unsigned int)(stats->latency_min / MILLION),
-        (unsigned int)(stats->latency_min % MILLION),
-        (unsigned int)(stats->latency_max / MILLION),
-        (unsigned int)(stats->latency_max % MILLION));
+        (unsigned int)(latency_avg % MILLION));
+    if (!now) {
+        printf(" (min %u.%06u, max %u.%06u)\n",
+            (unsigned int)(stats->latency_min / MILLION),
+            (unsigned int)(stats->latency_min % MILLION),
+            (unsigned int)(stats->latency_max / MILLION),
+            (unsigned int)(stats->latency_max % MILLION));
+    } else {
+        printf("\n");
+    }
+
     if (stats->num_completed > 1) {
         printf("  Latency StdDev (s):   %f\n",
             stddev(stats->latency_sum_squares, stats->latency_sum,
                 stats->num_completed)
                 / MILLION);
+#ifdef USE_HISTOGRAMS
+        if (config->latency_histogram)
+            print_histogram(stats->latency, "answer count");
+#endif
     }
 
     printf("\n");
@@ -336,32 +444,56 @@ print_statistics(const config_t* config, const times_t* times, stats_t* stats)
     printf("Connection Statistics:\n\n");
     printf("  Reconnections:        %" PRIu64 "\n\n", stats->num_conn_reconnect);
     latency_avg = PERF_SAFE_DIV(stats->conn_latency_sum, stats->num_conn_completed);
-    printf("  Average Latency (s):  %u.%06u (min %u.%06u, max %u.%06u)\n",
+    printf("  Average Latency (s):  %u.%06u",
         (unsigned int)(latency_avg / MILLION),
-        (unsigned int)(latency_avg % MILLION),
-        (unsigned int)(stats->conn_latency_min / MILLION),
-        (unsigned int)(stats->conn_latency_min % MILLION),
-        (unsigned int)(stats->conn_latency_max / MILLION),
-        (unsigned int)(stats->conn_latency_max % MILLION));
+        (unsigned int)(latency_avg % MILLION));
+    if (!now) {
+        printf(" (min %u.%06u, max %u.%06u)\n",
+            (unsigned int)(stats->conn_latency_min / MILLION),
+            (unsigned int)(stats->conn_latency_min % MILLION),
+            (unsigned int)(stats->conn_latency_max / MILLION),
+            (unsigned int)(stats->conn_latency_max % MILLION));
+    } else {
+        printf("\n");
+    }
     if (stats->num_conn_completed > 1) {
         printf("  Latency StdDev (s):   %f\n",
             stddev(stats->conn_latency_sum_squares, stats->conn_latency_sum, stats->num_conn_completed) / MILLION);
+#ifdef USE_HISTOGRAMS
+        if (config->latency_histogram)
+            print_histogram(stats->latency, "connection count");
+#endif
     }
 
     printf("\n");
 }
 
+/*
+ * Caller must free() stats->latency and stats->conn_latency.
+ */
 static void
 sum_stats(const config_t* config, stats_t* total)
 {
     unsigned int i, j;
 
     memset(total, 0, sizeof(*total));
+#ifdef USE_HISTOGRAMS
+    if (config->latency_histogram) {
+        total->latency      = hg64_create(HISTOGRAM_SIGBITS);
+        total->conn_latency = hg64_create(HISTOGRAM_SIGBITS);
+    }
+#endif
 
     for (i = 0; i < config->threads; i++) {
         stats_t* stats = &threads[i].stats;
+#ifdef USE_HISTOGRAMS
+        if (config->latency_histogram) {
+            hg64_merge(total->latency, stats->latency);
+            hg64_merge(total->conn_latency, stats->conn_latency);
+        }
+#endif
 
-        for (j = 0; j < 16; j++)
+        for (j = 0; j < DNSPERF_STATS_RCODECOUNTS; j++)
             total->rcodecounts[j] += stats->rcodecounts[j];
 
         total->num_sent += stats->num_sent;
@@ -499,6 +631,12 @@ setup(int argc, char** argv, config_t* config)
         "suppress messages/warnings, see man-page for list of message types", NULL, &local_suppress);
     perf_long_opt_add("num-queries-per-conn", perf_opt_uint, "queries",
         "Number of queries to send per connection", NULL, &config->num_queries_per_conn);
+    perf_long_opt_add("verbose-interval-stats", perf_opt_boolean, NULL,
+        "print detailed statistics for each stats_interval", NULL, &config->verbose_interval_stats);
+#ifdef USE_HISTOGRAMS
+    perf_long_opt_add("latency-histogram", perf_opt_boolean, NULL,
+        "collect and print detailed latency histograms", NULL, &config->latency_histogram);
+#endif
 
     bool log_stdout = false;
     perf_opt_add('W', perf_opt_boolean, NULL, "log warnings and errors to stdout instead of stderr", NULL, &log_stdout);
@@ -574,14 +712,18 @@ setup(int argc, char** argv, config_t* config)
      * If we run more threads than max-qps, some threads will have
      * ->max_qps set to 0, and be unlimited.
      */
-    if (config->max_qps > 0 && config->threads > config->max_qps)
+    if (config->max_qps > 0 && config->threads > config->max_qps) {
+        perf_log_warning("requested max QPS limit (-Q %u) is lower than number of threads (-T %u), lowering number of threads", config->max_qps, config->threads);
         config->threads = config->max_qps;
+    }
 
     /*
      * We also can't run more threads than clients.
      */
-    if (config->threads > config->clients)
+    if (config->threads > config->clients) {
+        perf_log_warning("requested number of threads (-T %u) exceeds number of clients (-c %u), lowering number of threads\n", config->threads, config->clients);
         config->threads = config->clients;
+    }
 
 #ifndef HAVE_LDNS
     if (config->updates) {
@@ -636,6 +778,10 @@ query_move(threadinfo_t* tinfo, query_info* q, query_move_op op)
 static inline uint64_t
 num_outstanding(const stats_t* stats)
 {
+    /* make sure negative values aren't returned */
+    if (stats->num_completed + stats->num_timedout > stats->num_sent) {
+        return 0;
+    }
     return stats->num_sent - stats->num_completed - stats->num_timedout;
 }
 
@@ -920,7 +1066,10 @@ recv_one(threadinfo_t* tinfo, int which_sock,
     }
     if (!n) {
         // Treat connection closed like try again until reconnection features are in
-        *saved_errnop = EAGAIN;
+        if (!*saved_errnop) {
+            // only set this if there was no error before to allow above error check to overwrite EAGAIN
+            *saved_errnop = EAGAIN;
+        }
         return false;
     }
     recvd->sock           = tinfo->socks[which_sock];
@@ -1006,8 +1155,6 @@ do_recv(void* arg)
                     break;
                 }
                 bit_set(socketbits, current_socket);
-                if (saved_errno != EAGAIN)
-                    break;
             }
             if (j == tinfo->nsocks)
                 break;
@@ -1039,11 +1186,13 @@ do_recv(void* arg)
                 perf_log_warning("received short response");
                 continue;
             }
-            if (recvd[i].unexpected && !tinfo->config->suppress.unexpected) {
-                perf_log_warning("received a response with an "
-                                 "unexpected (maybe timed out) "
-                                 "id: %u",
-                    recvd[i].qid);
+            if (recvd[i].unexpected) {
+                if (!tinfo->config->suppress.unexpected) {
+                    perf_log_warning("received a response with an "
+                                     "unexpected (maybe timed out) "
+                                     "id: %u",
+                        recvd[i].qid);
+                }
                 continue;
             }
             latency = recvd[i].when - recvd[i].sent;
@@ -1061,6 +1210,11 @@ do_recv(void* arg)
             stats->total_response_size += recvd[i].size;
             stats->rcodecounts[recvd[i].rcode]++;
             stats->latency_sum += latency;
+#ifdef USE_HISTOGRAMS
+            if (stats->latency) {
+                hg64_inc(stats->latency, latency);
+            }
+#endif
             stats->latency_sum_squares += (latency * latency);
             if (latency < stats->latency_min || stats->num_completed == 1)
                 stats->latency_min = latency;
@@ -1097,18 +1251,17 @@ static void*
 do_interval_stats(void* arg)
 {
     threadinfo_t*          tinfo;
-    stats_t                total;
+    stats_t                total = {};
+    stats_t                last  = {};
+    stats_t                diff  = {};
     uint64_t               now;
     uint64_t               last_interval_time;
-    uint64_t               last_completed;
     uint64_t               interval_time;
-    uint64_t               num_completed;
     double                 qps;
     struct perf_net_socket sock = { .mode = sock_pipe, .fd = threadpipe[0] };
 
     tinfo              = arg;
     last_interval_time = tinfo->times->start_time;
-    last_completed     = 0;
 
     wait_for_start();
     while (perf_os_waituntilreadable(&sock, threadpipe[0],
@@ -1117,13 +1270,23 @@ do_interval_stats(void* arg)
         now = perf_get_time();
         sum_stats(tinfo->config, &total);
         interval_time = now - last_interval_time;
-        num_completed = total.num_completed - last_completed;
-        qps           = num_completed / (((double)interval_time) / MILLION);
-        perf_log_printf("%u.%06u: %.6lf",
-            (unsigned int)(now / MILLION),
-            (unsigned int)(now % MILLION), qps);
+
+        if (tinfo->config->verbose_interval_stats) {
+            diff_stats(tinfo->config, &last, &total, &diff);
+            print_statistics(tinfo->config, tinfo->times, &diff, now, interval_time);
+        } else {
+            qps = (total.num_completed - last.num_completed) / (((double)interval_time) / MILLION);
+            perf_log_printf("%u.%06u: %.6lf",
+                (unsigned int)(now / MILLION),
+                (unsigned int)(now % MILLION), qps);
+        }
+
         last_interval_time = now;
-        last_completed     = total.num_completed;
+#ifdef USE_HISTOGRAMS
+        free(last.latency);
+        free(last.conn_latency);
+#endif
+        last = total;
     }
 
     return NULL;
@@ -1189,6 +1352,11 @@ static void perf__net_event(struct perf_net_socket* sock, perf_socket_event_t ev
     case perf_socket_event_connected:
         stats->num_conn_completed++;
 
+#ifdef USE_HISTOGRAMS
+        if (stats->conn_latency) {
+            hg64_inc(stats->conn_latency, elapsed_time);
+        }
+#endif
         stats->conn_latency_sum += elapsed_time;
         stats->conn_latency_sum_squares += (elapsed_time * elapsed_time);
         if (elapsed_time < stats->conn_latency_min || stats->num_conn_completed == 1)
@@ -1218,6 +1386,12 @@ threadinfo_init(threadinfo_t* tinfo, const config_t* config,
 
     perf_list_init(tinfo->outstanding_queries);
     perf_list_init(tinfo->unused_queries);
+#ifdef USE_HISTOGRAMS
+    if (config->latency_histogram) {
+        tinfo->stats.latency      = hg64_create(HISTOGRAM_SIGBITS);
+        tinfo->stats.conn_latency = hg64_create(HISTOGRAM_SIGBITS);
+    }
+#endif
     for (i = 0; i < NQIDS; i++) {
         perf_link_init(&tinfo->queries[i]);
         perf_list_append(tinfo->unused_queries, &tinfo->queries[i]);
@@ -1240,11 +1414,15 @@ threadinfo_init(threadinfo_t* tinfo, const config_t* config,
     /*
      * We can't have more than 64k outstanding queries per thread.
      */
-    if (tinfo->max_outstanding > NQIDS)
+    if (tinfo->max_outstanding > NQIDS) {
+        perf_log_warning("requested number of outstanding queries (-q %u) per single thread (-T) exceeds built-in maximum %u, adjusting\n", tinfo->max_outstanding, NQIDS);
         tinfo->max_outstanding = NQIDS;
+    }
 
-    if (tinfo->nsocks > MAX_SOCKETS)
+    if (tinfo->nsocks > MAX_SOCKETS) {
+        perf_log_warning("requested number of clients (-c %u) per thread (-T) exceeds built-in maximum %u, adjusting\n", tinfo->nsocks, MAX_SOCKETS);
         tinfo->nsocks = MAX_SOCKETS;
+    }
 
     if (!(tinfo->socks = calloc(tinfo->nsocks, sizeof(*tinfo->socks)))) {
         perf_log_fatal("out of memory");
@@ -1383,7 +1561,7 @@ int main(int argc, char** argv)
     print_final_status(&config);
 
     sum_stats(&config, &total_stats);
-    print_statistics(&config, &times, &total_stats);
+    print_statistics(&config, &times, &total_stats, 0, 0);
     perf_net_stats_print(config.mode);
 
     cleanup(&config);
diff --git a/src/edns.c b/src/edns.c
index fa66cc4..d3a0608 100644
--- a/src/edns.c
+++ b/src/edns.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/edns.h b/src/edns.h
index 8064cc4..bcd6822 100644
--- a/src/edns.h
+++ b/src/edns.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/ext/hg64.c b/src/ext/hg64.c
new file mode 100644
index 0000000..9cd4b4f
--- /dev/null
+++ b/src/ext/hg64.c
@@ -0,0 +1,327 @@
+/*
+ * hg64 - 64-bit histograms
+ *
+ * Written by Tony Finch <dot@dotat.at> <fanf@isc.org>
+ *
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <stdatomic.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "hg64.h"
+
+/* number of bins is same as number of bits in a value */
+#define BINS 64
+
+typedef atomic_uint_fast64_t counter;
+typedef _Atomic(counter*)    bin_ptr;
+
+struct hg64 {
+    unsigned sigbits;
+    bin_ptr  bin[BINS];
+};
+
+static inline counter*
+get_bin(hg64* hg, unsigned b)
+{
+    /* key_to_new_counter() below has the matching store / release */
+    return (atomic_load_explicit(&hg->bin[b], memory_order_acquire));
+}
+
+/*
+ * when we only care about the histogram precision
+ */
+struct hg64p {
+    unsigned sigbits;
+};
+
+#ifdef __has_attribute
+#if __has_attribute(__transparent_union__)
+#define TRANSPARENT __attribute__((__transparent_union__))
+#endif
+#endif
+
+#ifdef TRANSPARENT
+
+typedef union hg64u {
+    hg64*               hg;
+    const struct hg64p* hp;
+} hg64u TRANSPARENT;
+
+#define hg64p(hu) ((hu).hp)
+#else
+
+typedef void* hg64u;
+
+#define hg64p(hu) ((const struct hg64p*)(hu))
+#endif
+
+/*
+ * The bins arrays have a static size for simplicity, but that means We
+ * waste a little extra space that could be saved by omitting the
+ * exponents that land in the denormal number bin. The following macros
+ * calculate (at run time) the exact number of keys when we need to do
+ * accurate bounds checks.
+ */
+#define DENORMALS(hp) ((hp)->sigbits - 1)
+#define EXPONENTS(hp) (BINS - DENORMALS(hp))
+#define MANTISSAS(hp) (1 << (hp)->sigbits)
+#define KEYS(hp) (EXPONENTS(hp) * MANTISSAS(hp))
+
+#define BINSIZE(hp) MANTISSAS(hp)
+
+/**********************************************************************/
+
+#define OUTARG(ptr, val) (void)(((ptr) != NULL) && (bool)(*(ptr) = (val)))
+
+/**********************************************************************/
+
+hg64* hg64_create(unsigned sigbits)
+{
+    if (sigbits < 1 || 15 < sigbits) {
+        return (NULL);
+    }
+    hg64* hg    = malloc(sizeof(*hg));
+    hg->sigbits = sigbits;
+    /*
+     * it is probably portable to zero-initialize atomics but the
+     * C standard says we shouldn't rely on it; but this loop
+     * should optimize to memset() on most target systems
+     */
+    for (unsigned b = 0; b < BINS; b++) {
+        atomic_init(&hg->bin[b], NULL);
+    }
+    return (hg);
+}
+
+void hg64_destroy(hg64* hg)
+{
+    for (unsigned b = 0; b < BINS; b++) {
+        free(get_bin(hg, b));
+    }
+    *hg = (hg64) { 0 };
+    free(hg);
+}
+
+/**********************************************************************/
+
+static inline uint64_t
+key_to_minval(hg64u hu, unsigned key)
+{
+    unsigned binsize  = BINSIZE(hg64p(hu));
+    unsigned exponent = (key / binsize) - 1;
+    uint64_t mantissa = (key % binsize) + binsize;
+    return (key < binsize ? key : mantissa << exponent);
+}
+
+/*
+ * don't shift by 64, and don't underflow exponent; instead,
+ * reduce shift by 1 for each hazard and pre-shift UINT64_MAX
+ */
+static inline uint64_t
+key_to_maxval(hg64u hu, unsigned key)
+{
+    unsigned binsize = BINSIZE(hg64p(hu));
+    unsigned shift   = 63 - (key / binsize);
+    uint64_t range   = UINT64_MAX / 4 >> shift;
+    return (key_to_minval(hu, key) + range);
+}
+
+/*
+ * This branchless conversion is due to Paul Khuong: see bin_down_of() in
+ * https://pvk.ca/Blog/2015/06/27/linear-log-bucketing-fast-versatile-simple/
+ */
+static inline unsigned
+value_to_key(hg64u hu, uint64_t value)
+{
+    /* fast path */
+    const struct hg64p* hp = hg64p(hu);
+    /* ensure that denormal numbers are all in the same bin */
+    uint64_t binned = value | BINSIZE(hp);
+    int      clz    = __builtin_clzll((unsigned long long)(binned));
+    /* actually 1 less than the exponent except for denormals */
+    unsigned exponent = 63 - hp->sigbits - clz;
+    /* mantissa has leading bit set except for denormals */
+    unsigned mantissa = value >> exponent;
+    /* leading bit of mantissa adds one to exponent */
+    return ((exponent << hp->sigbits) + mantissa);
+}
+
+static counter*
+key_to_new_counter(hg64* hg, unsigned key)
+{
+    /* slow path */
+    unsigned binsize = BINSIZE(hg);
+    unsigned b       = key / binsize;
+    unsigned c       = key % binsize;
+    counter* old_bp  = NULL;
+    counter* new_bp  = malloc(sizeof(counter) * binsize);
+    /* see comment in hg64_create() above */
+    for (unsigned i = 0; i < binsize; i++) {
+        atomic_init(new_bp + i, 0);
+    }
+    bin_ptr* bpp = &hg->bin[b];
+    if (atomic_compare_exchange_strong_explicit(bpp, &old_bp, new_bp,
+            memory_order_acq_rel, memory_order_acquire)) {
+        return (new_bp + c);
+    } else {
+        /* lost the race, so use the winner's counters */
+        free(new_bp);
+        return (old_bp + c);
+    }
+}
+
+static inline counter*
+key_to_counter(hg64* hg, unsigned key)
+{
+    /* fast path */
+    unsigned binsize = BINSIZE(hg);
+    unsigned b       = key / binsize;
+    unsigned c       = key % binsize;
+    counter* bp      = get_bin(hg, b);
+    return (bp == NULL ? NULL : bp + c);
+}
+
+static inline uint64_t
+get_key_count(hg64* hg, unsigned key)
+{
+    counter* ctr = key_to_counter(hg, key);
+    return (ctr == NULL ? 0 : atomic_load_explicit(ctr, memory_order_relaxed));
+}
+
+static inline void
+add_key_count(hg64* hg, unsigned key, uint64_t inc)
+{
+    if (inc == 0)
+        return;
+    counter* ctr = key_to_counter(hg, key);
+    ctr          = ctr ? ctr : key_to_new_counter(hg, key);
+    atomic_fetch_add_explicit(ctr, inc, memory_order_relaxed);
+}
+
+/**********************************************************************/
+
+void hg64_inc(hg64* hg, uint64_t value)
+{
+    add_key_count(hg, value_to_key(hg, value), 1);
+}
+
+bool hg64_get(hg64* hg, unsigned key,
+    uint64_t* pmin, uint64_t* pmax, uint64_t* pcount)
+{
+    if (key < KEYS(hg)) {
+        OUTARG(pmin, key_to_minval(hg, key));
+        OUTARG(pmax, key_to_maxval(hg, key));
+        OUTARG(pcount, get_key_count(hg, key));
+        return (true);
+    } else {
+        return (false);
+    }
+}
+
+unsigned
+hg64_next(hg64* hg, unsigned key)
+{
+    key++;
+    while (key < KEYS(hg) && (key & (BINSIZE(hg) - 1)) == 0 && key_to_counter(hg, key) == NULL) {
+        key += BINSIZE(hg);
+    }
+    return (key);
+}
+
+/*
+ * https://fanf2.user.srcf.net/hermes/doc/antiforgery/stats.pdf
+ */
+void hg64_mean_variance(hg64* hg, double* pmean, double* pvar)
+{
+    double   pop   = 0.0;
+    double   mean  = 0.0;
+    double   sigma = 0.0;
+    uint64_t min, max, count;
+    for (unsigned key = 0;
+         hg64_get(hg, key, &min, &max, &count);
+         key = hg64_next(hg, key)) {
+        double delta = (double)min / 2.0 + (double)max / 2.0 - mean;
+        if (count != 0) { /* avoid division by zero */
+            pop += count;
+            mean += count * delta / pop;
+            sigma += count * delta * (min + max - mean);
+        }
+    }
+    OUTARG(pmean, mean);
+    OUTARG(pvar, sigma / pop);
+}
+
+/**********************************************************************/
+
+void hg64_merge(hg64* target, hg64* source)
+{
+    uint64_t count;
+    for (unsigned skey = 0;
+         hg64_get(source, skey, NULL, NULL, &count);
+         skey = hg64_next(source, skey)) {
+        uint64_t svmin = key_to_minval(source, skey);
+        uint64_t svmax = key_to_maxval(source, skey);
+        unsigned tkmin = value_to_key(target, svmin);
+        unsigned tkmax = value_to_key(target, svmax);
+        unsigned keys  = tkmax - tkmin + 1;
+        /* is there a more cunning way to spread out the remainder? */
+        uint64_t div = count / keys;
+        uint64_t rem = count % keys;
+        for (unsigned tkey = tkmin; tkey <= tkmax; tkey++) {
+            uint64_t inc = div + (uint64_t)(tkey < rem);
+            add_key_count(target, tkey, inc);
+        }
+    }
+}
+
+void hg64_diff(hg64* a, hg64* b, hg64* diff)
+{
+    assert((a->sigbits == b->sigbits) && (b->sigbits == diff->sigbits));
+    uint64_t count_a = 0;
+    uint64_t count_b = 0;
+    for (unsigned key = 0;
+         hg64_get(a, key, NULL, NULL, &count_a);
+         key++) {
+        hg64_get(b, key, NULL, NULL, &count_b);
+        add_key_count(diff, key, count_a - count_b);
+    }
+}
+
+unsigned hg64_min_key(hg64* hg)
+{
+    uint64_t pcount;
+    for (unsigned key = 0;
+         hg64_get(hg, key, NULL, NULL, &pcount);
+         key = hg64_next(hg, key)) {
+        if (pcount > 0)
+            return key;
+    }
+    return 0;
+}
+
+unsigned hg64_max_key(hg64* hg)
+{
+    unsigned last_key = 0;
+    uint64_t pcount;
+    for (unsigned key = 0;
+         hg64_get(hg, key, NULL, NULL, &pcount);
+         key = hg64_next(hg, key)) {
+        if (pcount > 0)
+            last_key = key;
+    }
+    return last_key;
+}
diff --git a/src/ext/hg64.h b/src/ext/hg64.h
new file mode 100644
index 0000000..21ec3d3
--- /dev/null
+++ b/src/ext/hg64.h
@@ -0,0 +1,88 @@
+/*
+ * hg64 - 64-bit histograms
+ *
+ * Written by Tony Finch <dot@dotat.at> <fanf@isc.org>
+ *
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef HG64_H
+#define HG64_H 1
+
+typedef struct hg64 hg64;
+
+/*
+ * Allocate a new histogram. `sigbits` must be between 1 and 15
+ * inclusive; it is the number of significant bits of each value
+ * to use when mapping values to buckets.
+ */
+hg64* hg64_create(unsigned sigbits);
+
+/*
+ * Free the memory used by a histogram
+ */
+void hg64_destroy(hg64* hg);
+
+/*
+ * Add 1 to the value's bucket
+ */
+void hg64_inc(hg64* hg, uint64_t value);
+
+/*
+ * Get information about a bucket. This can be used as an iterator,
+ * by initializing `key` to zero and incrementing by one or using
+ * `hg64_next()` until `hg64_get()` returns `false`. The number of
+ * iterations is a little less than `1 << (6 + sigbits)`.
+ *
+ * If `pmin` is non-NULL it is set to the bucket's minimum inclusive value.
+ *
+ * If `pmax` is non-NULL it is set to the bucket's maximum inclusive value.
+ *
+ * If `pcount` is non-NULL it is set to the bucket's counter, which
+ * can be zero. (Empty buckets are included in the iterator.)
+ */
+bool hg64_get(hg64* hg, unsigned key,
+    uint64_t* pmin, uint64_t* pmax, uint64_t* pcount);
+
+/*
+ * Skip to the next key, omitting groups of nonexistent buckets.
+ */
+unsigned hg64_next(hg64* hg, unsigned key);
+
+/*
+ * Get summary statistics about the histogram.
+ *
+ * If `pmean` is non-NULL it is set to the mean of the recorded data.
+ *
+ * If `pvar` is non-NULL it is set to the variance of the recorded
+ * data. The standard deviation is the square root of the variance.
+ */
+void hg64_mean_variance(hg64* hg, double* pmean, double* pvar);
+
+/*
+ * Increase the counts in `target` by the counts recorded in `source`
+ */
+void hg64_merge(hg64* target, hg64* source);
+
+/*
+ * diff = a - b
+ */
+void hg64_diff(hg64* a, hg64* b, hg64* diff);
+
+/*
+ * Get highest key with non-zero value. Returns 0 if all values are 0.
+ */
+unsigned hg64_max_key(hg64* hg);
+
+/*
+ * Get lowest key with non-zero value. Returns 0 if all values are 0.
+ */
+unsigned hg64_min_key(hg64* hg);
+
+#endif
diff --git a/src/parse_uri.c b/src/ext/parse_uri.c
index fa74c85..fa74c85 100644
--- a/src/parse_uri.c
+++ b/src/ext/parse_uri.c
diff --git a/src/parse_uri.h b/src/ext/parse_uri.h
index bb69e79..bb69e79 100644
--- a/src/parse_uri.h
+++ b/src/ext/parse_uri.h
diff --git a/src/list.h b/src/list.h
index d52ad04..47064fb 100644
--- a/src/list.h
+++ b/src/list.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/log.c b/src/log.c
index e807dcc..661e373 100644
--- a/src/log.c
+++ b/src/log.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/log.h b/src/log.h
index e922ca1..040a29a 100644
--- a/src/log.h
+++ b/src/log.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/net.c b/src/net.c
index ca3750f..89e75e0 100644
--- a/src/net.c
+++ b/src/net.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/net.h b/src/net.h
index 89af773..1624be6 100644
--- a/src/net.h
+++ b/src/net.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/net_doh.c b/src/net_doh.c
index f483e0d..dafd736 100644
--- a/src/net_doh.c
+++ b/src/net_doh.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
@@ -28,7 +28,7 @@
 
 #include "net.h"
 #include "edns.h"
-#include "parse_uri.h"
+#include "ext/parse_uri.h"
 #include "log.h"
 #include "strerror.h"
 #include "util.h"
@@ -324,6 +324,8 @@ static ssize_t perf__doh_recv(struct perf_net_socket* sock, void* buf, size_t le
                 return -1;
             case SSL_ERROR_SYSCALL:
                 switch (errno) {
+                case EBADF:
+                    // treat this as a retry, can happen if sendto is reconnecting
                 case ECONNREFUSED:
                 case ECONNRESET:
                 case ENOTCONN:
diff --git a/src/net_dot.c b/src/net_dot.c
index 9fd718d..7e58a73 100644
--- a/src/net_dot.c
+++ b/src/net_dot.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
@@ -177,6 +177,8 @@ static ssize_t perf__dot_recv(struct perf_net_socket* sock, void* buf, size_t le
                 break;
             case SSL_ERROR_SYSCALL:
                 switch (errno) {
+                case EBADF:
+                    // treat this as a retry, can happen if sendto is reconnecting
                 case ECONNREFUSED:
                 case ECONNRESET:
                 case ENOTCONN:
diff --git a/src/net_tcp.c b/src/net_tcp.c
index 61676fc..026dcce 100644
--- a/src/net_tcp.c
+++ b/src/net_tcp.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
@@ -171,6 +171,8 @@ static ssize_t perf__tcp_recv(struct perf_net_socket* sock, void* buf, size_t le
             return 0;
         } else if (n < 0) {
             switch (errno) {
+            case EBADF:
+                // treat this as a retry, can happen if sendto is reconnecting
             case ECONNREFUSED:
             case ECONNRESET:
             case ENOTCONN:
diff --git a/src/net_udp.c b/src/net_udp.c
index 5ca100f..2efc384 100644
--- a/src/net_udp.c
+++ b/src/net_udp.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/opt.c b/src/opt.c
index d65a0f8..7a0f346 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
@@ -238,39 +238,57 @@ static int perf_opt_long_parse(char* optarg)
     ssize_t optlen;
     char*   arg;
 
-    // TODO: Allow boolean not to have =/value
-    if (!(arg = strchr(optarg, '='))) {
-        return -1;
-    }
-    optlen = arg - optarg;
-    if (optlen < 1) {
-        return -1;
+    if ((arg = strchr(optarg, '='))) {
+        arg++;
+        optlen = arg - optarg;
+        if (optlen < 1) {
+            return -1;
+        }
+    } else {
+        optlen = strlen(optarg);
     }
-    arg++;
 
     long_opt_t* opt = longopts;
     while (opt) {
         if (!strncmp(optarg, opt->name, optlen)) {
             switch (opt->type) {
             case perf_opt_string:
+                if (!arg) {
+                    return -1;
+                }
                 *opt->u.stringp = arg;
                 break;
             case perf_opt_boolean:
                 *opt->u.boolp = true;
                 break;
             case perf_opt_uint:
+                if (!arg) {
+                    return -1;
+                }
                 *opt->u.uintp = parse_uint(opt->desc, arg, 1, 0xFFFFFFFF);
                 break;
             case perf_opt_zpint:
+                if (!arg) {
+                    return -1;
+                }
                 *opt->u.uintp = parse_uint(opt->desc, arg, 0, 0xFFFFFFFF);
                 break;
             case perf_opt_timeval:
+                if (!arg) {
+                    return -1;
+                }
                 *opt->u.uint64p = parse_timeval(opt->desc, arg);
                 break;
             case perf_opt_double:
+                if (!arg) {
+                    return -1;
+                }
                 *opt->u.doublep = parse_double(opt->desc, arg);
                 break;
             case perf_opt_port:
+                if (!arg) {
+                    return -1;
+                }
                 *opt->u.portp = parse_uint(opt->desc, arg, 0, 0xFFFF);
                 break;
             }
@@ -284,10 +302,10 @@ static int perf_opt_long_parse(char* optarg)
 
 void perf_long_opt_usage(void)
 {
-    fprintf(stderr, "Usage: %s ... -O <name>=<value> ...\n\nAvailable long options:\n", progname);
+    fprintf(stderr, "Usage: %s ... -O <name>[=<value>] ...\n\nAvailable long options:\n", progname);
     long_opt_t* opt = longopts;
     while (opt) {
-        fprintf(stderr, "  %s: %s", opt->name, opt->help);
+        fprintf(stderr, "  %s%s: %s", opt->name, opt->type != perf_opt_boolean ? "=<val>" : "", opt->help);
         if (opt->defval) {
             fprintf(stderr, " (default: %s)", opt->defval);
         }
diff --git a/src/opt.h b/src/opt.h
index e30ea8c..82a15a2 100644
--- a/src/opt.h
+++ b/src/opt.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/os.c b/src/os.c
index 24304bc..a36cbed 100644
--- a/src/os.c
+++ b/src/os.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/os.h b/src/os.h
index b21e6ed..0d9e8c5 100644
--- a/src/os.h
+++ b/src/os.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/qtype.c b/src/qtype.c
index c41348f..bce24f3 100644
--- a/src/qtype.c
+++ b/src/qtype.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/qtype.h b/src/qtype.h
index 87e157c..d136870 100644
--- a/src/qtype.h
+++ b/src/qtype.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/resperf-report b/src/resperf-report
index 2d154bc..7c1431d 100755
--- a/src/resperf-report
+++ b/src/resperf-report
@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# Copyright 2019-2022 OARC, Inc.
+# Copyright 2019-2023 OARC, Inc.
 # Copyright 2017-2018 Akamai Technologies
 # Copyright 2006-2016 Nominum, Inc.
 # All rights reserved.
diff --git a/src/resperf.1.in b/src/resperf.1.in
index 28f9bbb..1c31b35 100644
--- a/src/resperf.1.in
+++ b/src/resperf.1.in
@@ -1,4 +1,4 @@
-.\" Copyright 2019-2022 OARC, Inc.
+.\" Copyright 2019-2023 OARC, Inc.
 .\" Copyright 2017-2018 Akamai Technologies
 .\" Copyright 2006-2016 Nominum, Inc.
 .\" All rights reserved.
diff --git a/src/resperf.c b/src/resperf.c
index aa58dc0..ae4f9cd 100644
--- a/src/resperf.c
+++ b/src/resperf.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/result.h b/src/result.h
index 7670a91..b50716b 100644
--- a/src/result.h
+++ b/src/result.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/strerror.c b/src/strerror.c
index 1a771f8..d870cb1 100644
--- a/src/strerror.c
+++ b/src/strerror.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/strerror.h b/src/strerror.h
index 915e06d..312b148 100644
--- a/src/strerror.h
+++ b/src/strerror.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/test/test1.sh b/src/test/test1.sh
index 945aab3..cd6af3c 100755
--- a/src/test/test1.sh
+++ b/src/test/test1.sh
@@ -2,3 +2,8 @@
 
 ../dnsperf -h
 ../resperf -h
+
+! ../dnsperf -O suppress
+! ../dnsperf -O suppress=
+! ../resperf -O suppress
+! ../resperf -O suppress=
diff --git a/src/tsig.c b/src/tsig.c
index ce10eea..b697141 100644
--- a/src/tsig.c
+++ b/src/tsig.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/tsig.h b/src/tsig.h
index 637b348..b69c2d1 100644
--- a/src/tsig.h
+++ b/src/tsig.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.
diff --git a/src/util.h b/src/util.h
index c59e459..ae821b0 100644
--- a/src/util.h
+++ b/src/util.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 OARC, Inc.
+ * Copyright 2019-2023 OARC, Inc.
  * Copyright 2017-2018 Akamai Technologies
  * Copyright 2006-2016 Nominum, Inc.
  * All rights reserved.