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You may want to know where and how long a task is sleeping. A callchain
may be found in sched_switch and a time slice in stat_iowait, so I add
handler in perf inject for merging this events.
My code saves sched_switch event for each process and when it meets
stat_iowait, it reports the sched_switch event, because this event
contains a correct callchain. By another words it replaces all
stat_iowait events on proper sched_switch events.
I use the next sequence of commands for testing:
perf record -e sched:sched_stat_sleep -e sched:sched_switch \
-e sched:sched_process_exit -g -o ~/perf.data.raw \
~/test-program
perf inject -v -s -i ~/perf.data.raw -o ~/perf.data
perf report --stdio -i ~/perf.data
100.00% foo [kernel.kallsyms] [k] __schedule
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--- __schedule
schedule
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|--79.75%-- schedule_hrtimeout_range_clock
| schedule_hrtimeout_range
| poll_schedule_timeout
| do_select
| core_sys_select
| sys_select
| system_call_fastpath
| __select
| __libc_start_main
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--20.25%-- do_nanosleep
hrtimer_nanosleep
sys_nanosleep
system_call_fastpath
__GI___libc_nanosleep
__libc_start_main
And here is test-program.c:
#include<unistd.h>
#include<time.h>
#include<sys/select.h>
int main()
{
struct timespec ts1;
struct timeval tv1;
int i;
long s;
for (i = 0; i < 10; i++) {
ts1.tv_sec = 0;
ts1.tv_nsec = 10000000;
nanosleep(&ts1, NULL);
tv1.tv_sec = 0;
tv1.tv_usec = 40000;
select(0, NULL, NULL, NULL,&tv1);
}
return 1;
}
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1344344165-369636-4-git-send-email-avagin@openvz.org
[ committer note: Made it use evsel->handler ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
47 lines
1.1 KiB
Plaintext
47 lines
1.1 KiB
Plaintext
perf-inject(1)
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==============
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NAME
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----
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perf-inject - Filter to augment the events stream with additional information
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SYNOPSIS
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--------
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[verse]
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'perf inject <options>'
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DESCRIPTION
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-----------
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perf-inject reads a perf-record event stream and repipes it to stdout. At any
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point the processing code can inject other events into the event stream - in
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this case build-ids (-b option) are read and injected as needed into the event
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stream.
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Build-ids are just the first user of perf-inject - potentially anything that
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needs userspace processing to augment the events stream with additional
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information could make use of this facility.
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OPTIONS
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-------
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-b::
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--build-ids=::
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Inject build-ids into the output stream
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-v::
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--verbose::
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Be more verbose.
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-i::
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--input=::
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Input file name. (default: stdin)
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-o::
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--output=::
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Output file name. (default: stdout)
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-s::
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--sched-stat::
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Merge sched_stat and sched_switch for getting events where and how long
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tasks slept. sched_switch contains a callchain where a task slept and
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sched_stat contains a timeslice how long a task slept.
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SEE ALSO
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--------
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linkperf:perf-record[1], linkperf:perf-report[1], linkperf:perf-archive[1]
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