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>
2 files changed