perf trace: Allow configuring default for perf_event_attr.inherit
tip-bot for Arnaldo Carvalho de Melo
merge botCommit-ID: d32de87e734191698dd1834146ee65ebd0f5e240 Gitweb: https://git.kernel.org/tip/d32de87e734191698dd1834146ee65ebd0f5e240 Author: Arnaldo Carvalho de Melo <[email protected]> AuthorDate: Fri, 14 Dec 2018 11:06:16 -0300 Committer: Arnaldo Carvalho de Melo <[email protected]> CommitDate: Tue, 18 Dec 2018 12:24:01 -0300
perf trace: Allow configuring default for perf_event_attr.inherit
I.f. if children should inherit the parent perf_event configuration, i.e. if we should trace children as well or just the parent.
The default is to follow children, to disable this and have a behaviour similar to strace, set this config option or use the --no_inherit 'perf trace' option.
E.g.:
Default:
# perf config trace.no_inherit
# trace -e clone,*sleep time sleep 1
0.000 time/21107 clone(clone_flags: CHILD_CLEARTID|CHILD_SETTID|0x11, newsp: 0, child_tidptr: 0x7f7b8f9ae810) = 21108 (time)
? time/21108 ... [continued]: clone()
0.691 sleep/21108 nanosleep(rqtp: 0x7ffed01d0540, rmtp: 0 ) = 0
0.00user 0.00system 0:01.00elapsed 0%CPU (0avgtext+0avgdata 1988maxresident)k
0inputs+0outputs (0major+76minor)pagefaults 0swaps
#Disable it:
# trace -e clone,*sleep time sleep 1
0.000 clone(clone_flags: CHILD_CLEARTID|CHILD_SETTID|0x11, newsp: 0, child_tidptr: 0x7ff41e100810) = 21414 (time)
0.00user 0.00system 0:01.00elapsed 0%CPU (0avgtext+0avgdata 1964maxresident)k
0inputs+0outputs (0major+76minor)pagefaults 0swaps
#Notice that since there is just one thread, the "comm/TID" column is suppressed.
Cc Adrian Hunter <[email protected]>
Cc Jiri Olsa <[email protected]>
Cc Luis Cláudio Gonçalves <[email protected]>
Cc Namhyung Kim <[email protected]>
Cc Wang Nan <[email protected]>
Signed-off-by Arnaldo Carvalho de Melo <[email protected]>
--- tools/perf/Documentation/perf-config.txt | 3 +++ tools/perf/builtin-trace.c | 2 ++ 2 files changed, 5 insertions(+)
tools/perf/Documentation/perf-config.txt +3 -0
@@ -529,6 +529,9 @@ trace.*:: activate the 'perf trace' logic that looks for syscall pointer contents after the normal tracepoint payload. + trace.no_inherit:: + Do not follow children threads. + trace.show_duration:: Show syscall duration.
tools/perf/builtin-trace.c +2 -0
@@ -3542,6 +3542,8 @@ static int trace__config(const char *var, const char *value, void *arg) trace->show_duration =perf_config_bool (var, value); }else if (!strcmp (var,"trace.show_zeros" )) { trace->show_zeros =perf_config_bool (var, value); + }else if (!strcmp (var,"trace.no_inherit" )) { + trace->opts.no_inherit =perf_config_bool (var, value); }return err;