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+.\" Copyright (C) 2014 Michael Kerrisk <mtk.manpages@gmail.com>
+.\"
+.\" SPDX-License-Identifier: Linux-man-pages-copyleft
+.\"
+.TH sprof 1 2024-05-02 "Linux man-pages (unreleased)"
+.SH NAME
+sprof \- read and display shared object profiling data
+.SH SYNOPSIS
+.nf
+.BR sprof " [\fIoption\fP]... \fIshared-object-path\fP \
+[\fIprofile-data-path\fP]"
+.fi
+.SH DESCRIPTION
+The
+.B sprof
+command displays a profiling summary for the
+shared object (shared library) specified as its first command-line argument.
+The profiling summary is created using previously generated
+profiling data in the (optional) second command-line argument.
+If the profiling data pathname is omitted, then
+.B sprof
+will attempt to deduce it using the soname of the shared object,
+looking for a file with the name
+.I <soname>.profile
+in the current directory.
+.SH OPTIONS
+The following command-line options specify the profile output
+to be produced:
+.TP
+.B \-\-call\-pairs
+.TQ
+.B \-c
+Print a list of pairs of call paths for the interfaces exported
+by the shared object,
+along with the number of times each path is used.
+.TP
+.B \-\-flat\-profile
+.TQ
+.B \-p
+Generate a flat profile of all of the functions in the monitored object,
+with counts and ticks.
+.TP
+.B \-\-graph
+.TQ
+.B \-q
+Generate a call graph.
+.P
+If none of the above options is specified,
+then the default behavior is to display a flat profile and a call graph.
+.P
+The following additional command-line options are available:
+.TP
+.B \-\-help
+.TQ
+.B \-?
+Display a summary of command-line options and arguments and exit.
+.TP
+.B \-\-usage
+Display a short usage message and exit.
+.TP
+.B \-\-version
+.TQ
+.B \-V
+Display the program version and exit.
+.SH STANDARDS
+GNU.
+.SH EXAMPLES
+The following example demonstrates the use of
+.BR sprof .
+The example consists of a main program that calls two functions
+in a shared object.
+First, the code of the main program:
+.P
+.in +4n
+.EX
+$ \fBcat prog.c\fP
+#include <stdlib.h>
+\&
+void x1(void);
+void x2(void);
+\&
+int
+main(int argc, char *argv[])
+{
+ x1();
+ x2();
+ exit(EXIT_SUCCESS);
+}
+.EE
+.in
+.P
+The functions
+.IR x1 ()
+and
+.IR x2 ()
+are defined in the following source file that is used to
+construct the shared object:
+.P
+.in +4n
+.EX
+$ \fBcat libdemo.c\fP
+#include <unistd.h>
+\&
+void
+consumeCpu1(int lim)
+{
+ for (unsigned int j = 0; j < lim; j++)
+ getppid();
+}
+\&
+void
+x1(void) {
+ for (unsigned int j = 0; j < 100; j++)
+ consumeCpu1(200000);
+}
+\&
+void
+consumeCpu2(int lim)
+{
+ for (unsigned int j = 0; j < lim; j++)
+ getppid();
+}
+\&
+void
+x2(void)
+{
+ for (unsigned int j = 0; j < 1000; j++)
+ consumeCpu2(10000);
+}
+.EE
+.in
+.P
+Now we construct the shared object with the real name
+.IR libdemo.so.1.0.1 ,
+and the soname
+.IR libdemo.so.1 :
+.P
+.in +4n
+.EX
+$ \fBcc \-g \-fPIC \-shared \-Wl,\-soname,libdemo.so.1 \e\fP
+ \fB\-o libdemo.so.1.0.1 libdemo.c\fP
+.EE
+.in
+.P
+Then we construct symbolic links for the library soname and
+the library linker name:
+.P
+.in +4n
+.EX
+$ \fBln \-sf libdemo.so.1.0.1 libdemo.so.1\fP
+$ \fBln \-sf libdemo.so.1 libdemo.so\fP
+.EE
+.in
+.P
+Next, we compile the main program, linking it against the shared object,
+and then list the dynamic dependencies of the program:
+.P
+.in +4n
+.EX
+$ \fBcc \-g \-o prog prog.c \-L. \-ldemo\fP
+$ \fBldd prog\fP
+ linux\-vdso.so.1 => (0x00007fff86d66000)
+ libdemo.so.1 => not found
+ libc.so.6 => /lib64/libc.so.6 (0x00007fd4dc138000)
+ /lib64/ld\-linux\-x86\-64.so.2 (0x00007fd4dc51f000)
+.EE
+.in
+.P
+In order to get profiling information for the shared object,
+we define the environment variable
+.B LD_PROFILE
+with the soname of the library:
+.P
+.in +4n
+.EX
+$ \fBexport LD_PROFILE=libdemo.so.1\fP
+.EE
+.in
+.P
+We then define the environment variable
+.B LD_PROFILE_OUTPUT
+with the pathname of the directory where profile output should be written,
+and create that directory if it does not exist already:
+.P
+.in +4n
+.EX
+$ \fBexport LD_PROFILE_OUTPUT=$(pwd)/prof_data\fP
+$ \fBmkdir \-p $LD_PROFILE_OUTPUT\fP
+.EE
+.in
+.P
+.B LD_PROFILE
+causes profiling output to be
+.I appended
+to the output file if it already exists,
+so we ensure that there is no preexisting profiling data:
+.P
+.in +4n
+.EX
+$ \fBrm \-f $LD_PROFILE_OUTPUT/$LD_PROFILE.profile\fP
+.EE
+.in
+.P
+We then run the program to produce the profiling output,
+which is written to a file in the directory specified in
+.BR LD_PROFILE_OUTPUT :
+.P
+.in +4n
+.EX
+$ \fBLD_LIBRARY_PATH=. ./prog\fP
+$ \fBls prof_data\fP
+libdemo.so.1.profile
+.EE
+.in
+.P
+We then use the
+.B sprof \-p
+option to generate a flat profile with counts and ticks:
+.P
+.in +4n
+.EX
+$ \fBsprof \-p libdemo.so.1 $LD_PROFILE_OUTPUT/libdemo.so.1.profile\fP
+Flat profile:
+\&
+Each sample counts as 0.01 seconds.
+ % cumulative self self total
+ time seconds seconds calls us/call us/call name
+ 60.00 0.06 0.06 100 600.00 consumeCpu1
+ 40.00 0.10 0.04 1000 40.00 consumeCpu2
+ 0.00 0.10 0.00 1 0.00 x1
+ 0.00 0.10 0.00 1 0.00 x2
+.EE
+.in
+.P
+The
+.B sprof \-q
+option generates a call graph:
+.P
+.in +4n
+.EX
+$ \fBsprof \-q libdemo.so.1 $LD_PROFILE_OUTPUT/libdemo.so.1.profile\fP
+\&
+index % time self children called name
+\&
+ 0.00 0.00 100/100 x1 [1]
+[0] 100.0 0.00 0.00 100 consumeCpu1 [0]
+\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-
+ 0.00 0.00 1/1 <UNKNOWN>
+[1] 0.0 0.00 0.00 1 x1 [1]
+ 0.00 0.00 100/100 consumeCpu1 [0]
+\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-
+ 0.00 0.00 1000/1000 x2 [3]
+[2] 0.0 0.00 0.00 1000 consumeCpu2 [2]
+\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-
+ 0.00 0.00 1/1 <UNKNOWN>
+[3] 0.0 0.00 0.00 1 x2 [3]
+ 0.00 0.00 1000/1000 consumeCpu2 [2]
+\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-
+.EE
+.in
+.P
+Above and below, the "<UNKNOWN>" strings represent identifiers that
+are outside of the profiled object (in this example, these are instances of
+.IR main() ).
+.P
+The
+.B sprof \-c
+option generates a list of call pairs and the number of their occurrences:
+.P
+.in +4n
+.EX
+$ \fBsprof \-c libdemo.so.1 $LD_PROFILE_OUTPUT/libdemo.so.1.profile\fP
+<UNKNOWN> x1 1
+x1 consumeCpu1 100
+<UNKNOWN> x2 1
+x2 consumeCpu2 1000
+.EE
+.in
+.SH SEE ALSO
+.BR gprof (1),
+.BR ldd (1),
+.BR ld.so (8)