Messages in this thread | | | Date | Tue, 15 Dec 2009 15:23:27 +0100 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 0/4] perf_event: introduce 'perf timer' to analyze timer's behavior |
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On Tue, Dec 15, 2009 at 07:17:03PM +0800, Xiao Guangrong wrote: > Hi, > > We introduce 'perf timer' in this patchset, it can analyze timer > latency and timer function handle time, the usage and result is > like below: > > # perf timer record > # perf timer lat --print-lat --print-handle > ------------------------------------------------------------------------------------------------------- > | Timer | TYPE | Avg-latency | Max-latency | Max-latency-at-TS |Max-lat-at-Task | > |0xf7ad1f5c |hrtimer |996068.500 ns|1607650 ns|10270128658526 |init | > |0xf7903f04 |timer |0.625 HZ|2 HZ|10270344082394 |swapper | > |0xf787a05c |hrtimer |200239.500 ns|359929 ns|10269316024808 |main | > |main :[ PROF]|itimer |0.000 HZ|0 HZ|10237021270557 |main | > |main :[VIRTUAL]|itimer |0.000 HZ|0 HZ|10257314773501 |main | > > ...... > > ------------------------------------------------------------------------------------------------------- > | Timer | TYPE | Avg-handle (ms)|Max-handle(ms)| Max-handle-at-TS(s)|Max-lat-at-func | > |0xf7ad1f5c |hrtimer |0.025 |0.025 |10270.129 |0xc016b5b0 | > |0xf7903f04 |timer |0.009 |0.011 |10260.342 |0xc0159240 | > |0xf787a05c |hrtimer |0.031 |0.062 |10267.018 |0xc014cc40 | > > And, in current code, it'll complain with below message when we use > 'perf timer lat': > > # ./perf timer lat > Warning: unknown op '{' > Warning: Error: expected type 5 but read 1 > Warning: failed to read event print fmt for hrtimer_start > Warning: unknown op '{' > Warning: Error: expected type 5 but read 1 > Warning: failed to read event print fmt for hrtimer_expire_entry
Oh and indeed we have some event format complexities to solve there.
cat /debug/tracing/events/timer/hrtimer_start/format
print fmt: "hrtimer=%p function=%pf expires=%llu softexpires=%llu", REC->hrtimer, REC->function, (unsigned long long)(((ktime_t) { .tv64 = REC->expires }).tv64), (unsigned long long)(((ktime_t) { .tv64 = REC->softexpires }).tv64)
We should try to simplify this, may be we should just expose __entry->expires as is.
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