Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/tools/perf/examples/bpf/5sec.c b/tools/perf/examples/bpf/5sec.c
new file mode 100644
index 000000000..b9c203219
--- /dev/null
+++ b/tools/perf/examples/bpf/5sec.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+    Description:
+
+    . Disable strace like syscall tracing (--no-syscalls), or try tracing
+      just some (-e *sleep).
+
+    . Attach a filter function to a kernel function, returning when it should
+      be considered, i.e. appear on the output.
+
+    . Run it system wide, so that any sleep of >= 5 seconds and < than 6
+      seconds gets caught.
+
+    . Ask for callgraphs using DWARF info, so that userspace can be unwound
+
+    . While this is running, run something like "sleep 5s".
+
+    . If we decide to add tv_nsec as well, then it becomes:
+
+      int probe(hrtimer_nanosleep, rqtp->tv_sec rqtp->tv_nsec)(void *ctx, int err, long sec, long nsec)
+
+      I.e. add where it comes from (rqtp->tv_nsec) and where it will be
+      accessible in the function body (nsec)
+
+    # perf trace --no-syscalls -e tools/perf/examples/bpf/5sec.c/call-graph=dwarf/
+         0.000 perf_bpf_probe:func:(ffffffff9811b5f0) tv_sec=5
+                                           hrtimer_nanosleep ([kernel.kallsyms])
+                                           __x64_sys_nanosleep ([kernel.kallsyms])
+                                           do_syscall_64 ([kernel.kallsyms])
+                                           entry_SYSCALL_64 ([kernel.kallsyms])
+                                           __GI___nanosleep (/usr/lib64/libc-2.26.so)
+                                           rpl_nanosleep (/usr/bin/sleep)
+                                           xnanosleep (/usr/bin/sleep)
+                                           main (/usr/bin/sleep)
+                                           __libc_start_main (/usr/lib64/libc-2.26.so)
+                                           _start (/usr/bin/sleep)
+    ^C#
+
+   Copyright (C) 2018 Red Hat, Inc., Arnaldo Carvalho de Melo <acme@redhat.com>
+*/
+
+#include <bpf.h>
+
+int probe(hrtimer_nanosleep, rqtp->tv_sec)(void *ctx, int err, long sec)
+{
+	return sec == 5;
+}
+
+license(GPL);