Messages in this thread | | | Date | Wed, 16 Dec 2009 09:19:18 +0800 | From | Xiao Guangrong <> | Subject | Re: [PATCH 0/4] perf_event: introduce 'perf timer' to analyze timer's behavior |
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Frederic Weisbecker wrote: > 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 | > > > > Cool! This is really a good work and a good idea. > > Just have some neats in mind. hrtimers and timers don't have the same latency and > granularity requirements. > > As you show it, timers have an HZ granularity and hrtimers are about nanoseconds, > and mixing them up in the same array of latency report is too messy. > They don't have the same granularity/latency scope so they should > be reported separately. >
Yeah, it has different unit and looks ugly :-(
but, the problem is we can't get HZ in userspace now, i'll export HZ by proc or other way and rectify 'perf timer' output in my next work
Thanks, Xiao
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