From d37ba880598654fda10b312331377cdca3edd574 Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Fri, 1 Apr 2016 13:26:42 +0000 Subject: [PATCH] perf bpf: Add sample types for 'bpf-output' event Before this patch we can see very large time in the events before the 'bpf-output' event. For example: # perf trace -vv -T --ev sched:sched_switch \ --ev bpf-output/no-inherit,name=evt/ \ --ev ./test_bpf_trace.c/map:channel.event=evt/ \ usleep 10 ... 18446744073709.551 (18446564645918.480 ms): usleep/4157 nanosleep(rqtp: 0x7ffd3f0dc4e0) ... 18446744073709.551 ( ): evt:Raise a BPF event!..) 179427791.076 ( ): perf_bpf_probe:func_begin:(ffffffff810eb9a0)) 179427791.081 ( ): sched:sched_switch:usleep:4157 [120] S ==> swapper/2:0 [120]) ... We can also see the differences between bpf-output events and breakpoint events: For bpf output event: sample_type IP|TID|RAW|IDENTIFIER For tracepoint events: sample_type IP|TID|TIME|CPU|PERIOD|RAW|IDENTIFIER This patch fix this differences by adding more sample type for bpf-output events. After this patch: # perf trace -vv -T --ev sched:sched_switch \ --ev bpf-output/no-inherit,name=evt/ \ --ev ./test_bpf_trace.c/map:channel.event=evt/ \ usleep 10 ... 179877370.878 ( 0.003 ms): usleep/5336 nanosleep(rqtp: 0x7ffff866c450) ... 179877370.878 ( ): evt:Raise a BPF event!..) 179877370.878 ( ): perf_bpf_probe:func_begin:(ffffffff810eb9a0)) 179877370.882 ( ): sched:sched_switch:usleep:5336 [120] S ==> swapper/4:0 [120]) 179877370.945 ( ): evt:Raise a BPF event!..) ... # ./perf trace -vv -T --ev sched:sched_switch \ --ev bpf-output/no-inherit,name=evt/ \ --ev ./test_bpf_trace.c/map:channel.event=evt/ \ usleep 10 2>&1 | grep sample_type sample_type IP|TID|TIME|ID|CPU|PERIOD|RAW sample_type IP|TID|TIME|ID|CPU|PERIOD|RAW sample_type IP|TID|TIME|ID|CPU|PERIOD|RAW sample_type IP|TID|TIME|ID|CPU|PERIOD|RAW sample_type IP|TID|TIME|ID|CPU|PERIOD|RAW sample_type IP|TID|TIME|ID|CPU|PERIOD|RAW The 'IDENTIFIER' info is not required because all events have the same sample_type. Committer notes: Further testing, on top of the changes making 'perf trace' avoid samples from events without PERF_SAMPLE_TIME: Before: # trace --ev bpf-output/no-inherit,name=evt/ --ev /home/acme/bpf/test_bpf_trace.c/map:channel.event=evt/ usleep 10 0.560 ( 0.001 ms): brk( ) = 0x55e5a1df8000 18446640227439.430 (18446640227438.859 ms): nanosleep(rqtp: 0x7ffc96643370) ... 18446640227439.430 ( ): evt:Raise a BPF event!..) 0.576 ( ): perf_bpf_probe:func_begin:(ffffffff81112460)) 18446640227439.430 ( ): evt:Raise a BPF event!..) 0.645 ( ): perf_bpf_probe:func_end:(ffffffff81112460 <- ffffffff81003d92)) 0.646 ( 0.076 ms): ... [continued]: nanosleep()) = 0 # After: # trace --ev bpf-output/no-inherit,name=evt/ --ev /home/acme/bpf/test_bpf_trace.c/map:channel.event=evt/ usleep 10 0.292 ( 0.001 ms): brk( ) = 0x55c7cd6e1000 0.302 ( 0.004 ms): nanosleep(rqtp: 0x7ffedd8bc0f0) ... 0.302 ( ): evt:Raise a BPF event!..) 0.303 ( ): perf_bpf_probe:func_begin:(ffffffff81112460)) 0.397 ( ): evt:Raise a BPF event!..) 0.397 ( ): perf_bpf_probe:func_end:(ffffffff81112460 <- ffffffff81003d92)) 0.398 ( 0.100 ms): ... [continued]: nanosleep()) = 0 Signed-off-by: Wang Nan Reported-and-Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Milian Wolff Cc: Namhyung Kim Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1459517202-42320-1-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evsel.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 738ce226002b..3fd7c2c72f4a 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -226,7 +226,8 @@ struct perf_evsel *perf_evsel__new_idx(struct perf_event_attr *attr, int idx) perf_evsel__init(evsel, attr, idx); if (perf_evsel__is_bpf_output(evsel)) { - evsel->attr.sample_type |= PERF_SAMPLE_RAW; + evsel->attr.sample_type |= (PERF_SAMPLE_RAW | PERF_SAMPLE_TIME | + PERF_SAMPLE_CPU | PERF_SAMPLE_PERIOD), evsel->attr.sample_period = 1; } -- 2.20.1