perf trace: Don't set the base timestamp using events without PERF_SAMPLE_TIME
tip-bot for Arnaldo Carvalho de Melo
merge botCommit-ID: 8a07a8094b6b6c3e195885ec31f4bd0be54aafaf Gitweb: http://git.kernel.org/tip/8a07a8094b6b6c3e195885ec31f4bd0be54aafaf Author: Arnaldo Carvalho de Melo <[email protected]> AuthorDate: Thu, 31 Mar 2016 15:19:39 -0300 Committer: Arnaldo Carvalho de Melo <[email protected]> CommitDate: Fri, 1 Apr 2016 18:46:25 -0300
perf trace: Don't set the base timestamp using events without PERF_SAMPLE_TIME
This was causing bogus values to be shown at the timestamp column:
Before:
# trace --ev bpf-output/no-inherit,name=evt/ --ev /home/acme/bpf/test_bpf_trace.c/map:channel.event=evt/ usleep 10 94631143.385 ( 0.001 ms): brk( ) = 0x555555757000 94631143.398 ( 0.003 ms): mmap(len: 4096, prot: READ|WRITE, flags: PRIVATE|ANONYMOUS, fd: -1) = 0x7ffff7ff6000 94631143.406 ( 0.004 ms): access(filename: 0xf7df9e10, mode: R ) = -1 ENOENT No such file or directory 94631143.412 ( 0.004 ms): open(filename: 0xf7df8761, flags: CLOEXEC) = 3 94631143.415 ( 0.002 ms): fstat(fd: 3, statbuf: 0x7fffffffd6b0 ) = 0 94631143.419 ( 0.003 ms): mmap(len: 106798, prot: READ, flags: PRIVATE, fd: 3) = 0x7ffff7fdb000 94631143.420 ( 0.001 ms): close(fd: 3 ) = 0 94631143.432 ( 0.004 ms): open(filename: 0xf7ff6640, flags: CLOEXEC) = 3 <SNIP>
After:
# trace --ev bpf-output/no-inherit,name=evt/ --ev /home/acme/bpf/test_bpf_trace.c/map:channel.event=evt/ usleep 10 0.022 ( 0.001 ms): brk( ) = 0x55d7668a6000 0.037 ( 0.003 ms): mmap(len: 4096, prot: READ|WRITE, flags: PRIVATE|ANONYMOUS, fd: -1) = 0x7f8fbeb97000 0.123 ( 0.083 ms): access(filename: 0xbe995e10, mode: R ) = -1 ENOENT No such file or directory 0.130 ( 0.004 ms): open(filename: 0xbe994761, flags: CLOEXEC) = 3 0.133 ( 0.002 ms): fstat(fd: 3, statbuf: 0x7fff6487a890 ) = 0 0.138 ( 0.003 ms): mmap(len: 106798, prot: READ, flags: PRIVATE, fd: 3) = 0x7f8fbeb7c000 0.140 ( 0.001 ms): close(fd: 3 ) = 0 0.151 ( 0.004 ms): open(filename: 0xbeb97640, flags: CLOEXEC) = 3 <SNIP>
Cc Adrian Hunter <[email protected]>
Cc David Ahern <[email protected]>
Cc Jiri Olsa <[email protected]>
Cc Milian Wolff <[email protected]>
Cc Namhyung Kim <[email protected]>
Cc Wang Nan <[email protected]>
Signed-off-by Arnaldo Carvalho de Melo <[email protected]>
--- tools/perf/builtin-trace.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
tools/perf/builtin-trace.c +11 -2
@@ -2401,10 +2401,19 @@ static bool skip_sample(struct trace *trace, struct perf_sample *sample) }static void trace__set_base_time (struct trace *trace, -struct perf_evsel *evsel__maybe_unused , +struct perf_evsel *evsel,struct perf_sample *sample) { -if (trace->base_time ==0 && !trace->full_time) +/* +* BPF events were not setting PERF_SAMPLE_TIME, so be more robust +* and don't use sample->time unconditionally, we may end up having +* some other event in the future without PERF_SAMPLE_TIME for good +* reason, i.e. we may not be interested in its timestamps, just in +* it taking place, picking some piece of information when it +* appears in our event stream (vfs_getname comes to mind). +*/ +if (trace->base_time ==0 && !trace->full_time && + (evsel->attr.sample_type &PERF_SAMPLE_TIME )) trace->base_time = sample->time; }