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| author |   Arnaldo Carvalho de Melo <acme@redhat.com> | 2016-04-11 15:49:11 -0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2016-04-11 22:18:19 -0300 |
| commit | 44621819ddc9d5d0bfd0b0616c6cf33c94189b67 (patch) | |
| tree | ffd8713f48d2e835debbea10b2809adc8e395c67 /tools/perf/Documentation/perf-trace.txt | |
| parent | perf evsel: Introduce fprintf_callchain() method out of fprintf_sym() (diff) | |
| download | linux-dev-44621819ddc9d5d0bfd0b0616c6cf33c94189b67.tar.xz linux-dev-44621819ddc9d5d0bfd0b0616c6cf33c94189b67.zip | |
perf trace: Exclude the kernel part of the callchain leading to a syscall
The kernel parts are not that useful:
# trace -m 512 -e nanosleep --call dwarf usleep 1
0.065 ( 0.065 ms): usleep/18732 nanosleep(rqtp: 0x7ffc4ee4e200) = 0
syscall_slow_exit_work ([kernel.kallsyms])
do_syscall_64 ([kernel.kallsyms])
return_from_SYSCALL_64 ([kernel.kallsyms])
__nanosleep (/usr/lib64/libc-2.22.so)
usleep (/usr/lib64/libc-2.22.so)
main (/usr/bin/usleep)
__libc_start_main (/usr/lib64/libc-2.22.so)
_start (/usr/bin/usleep)
#
So lets just use perf_event_attr.exclude_callchain_kernel to avoid
collecting it in the ring buffer:
# trace -m 512 -e nanosleep --call dwarf usleep 1
0.063 ( 0.063 ms): usleep/19212 nanosleep(rqtp: 0x7ffc3df10fb0) = 0
__nanosleep (/usr/lib64/libc-2.22.so)
usleep (/usr/lib64/libc-2.22.so)
main (/usr/bin/usleep)
__libc_start_main (/usr/lib64/libc-2.22.so)
_start (/usr/bin/usleep)
#
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-qctu3gqhpim0dfbcp9d86c91@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/Documentation/perf-trace.txt')
| -rw-r--r-- | tools/perf/Documentation/perf-trace.txt | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-trace.txt b/tools/perf/Documentation/perf-trace.txt index ed485df16409..1bbcf305d233 100644 --- a/tools/perf/Documentation/perf-trace.txt +++ b/tools/perf/Documentation/perf-trace.txt @@ -123,6 +123,9 @@ the thread executes on the designated CPUs. Default is to monitor all CPUs. man pages for details. The ones that are most useful in 'perf trace' are 'dwarf' and 'lbr', where available, try: 'perf trace --call-graph dwarf'. +--kernel-syscall-graph:: + Show the kernel callchains on the syscall exit path. + --event:: Trace other events, see 'perf list' for a complete list. |