Messages in this thread | | | Date | Thu, 31 Aug 2023 13:13:01 +0300 | Subject | Re: [PATCH v7 0/6] perf record: Track sideband events for all CPUs when tracing selected CPUs | From | Adrian Hunter <> |
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On 29/08/23 15:24, Ravi Bangoria wrote: >>> Number of actual samples are same ~38K. However, the perf.data file is 5x >>> bigger because of additional sideband data. >> >> Yes, if record system wide sideband data, the amount of sideband events will increase proportionally, which is expected. >> >>> >>> I'm pretty sure we don't need most of those additional data. So, thinking >>> loud, should we post-process perf.data file and filter out unnecessary data? >>> >> >> I wonder if we can add a new function in perf inject. > > Ok. perf inject is one option. But shall we do it bydefault in perf-record? > It's needed only when profiling target is set of cpus, not for systemwide or > per-process mode. > >> By reading perf.data and comparing tid of SAMPLE events and sideband events, we can filter out the sideband data of unmatched tasks. > > Yup. But AFAIK, perf-record keeps writing to perf.data and never does post- > processing on it. So adding support for this will take a bit of effort. Not > sure if we should do it as part of this series.
I agree there could be more work, but probably better for a separate patch set.
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