Messages in this thread | | | Subject | Re: [PATCH 0/2] perf/core: deliver PERF_RECORD_COMM and PERF_RECORD_MMAP side-band events to all online cpus | From | Yang Jihong <> | Date | Fri, 23 Jun 2023 13:48:39 +0800 |
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Hello,
On 2023/6/21 2:49, Adrian Hunter wrote: > On 20/06/23 18:55, Yang Jihong wrote: >> Tasks are migrated between cores due to scheduling. >> If perf samples specified CPUs, PERF_RECORD_COMM and PERF_RECORD_MMAP >> events need be deliver to all cores to avoids the problem that the comm >> and symbols cannot be parsed due to task migration to the target core. >> >> The specific scenarios are as follows: >> >> CPU0 CPU1 >> perf record -C 0 start >> taskA starts to be created and executed >> -> PERF_RECORD_COMM and PERF_RECORD_MMAP >> events only deliver to CPU1 >> ...... >> | >> migrate to CPU0 >> | >> Running on CPU0 <----------/ >> ... >> >> perf record -C 0 stop >> >> Now perf samples the PC of taskA. However, perf does not record the >> PERF_RECORD_COMM and PERF_RECORD_COMM events of taskA. >> Therefore, the comm and symbols of taskA cannot be parsed. > > perf record deals with this for PERF_RECORD_TEXT_POKE, by opening > the corresponding "dummy" event on each CPU irrespective of whether > the main events are on selected CPUs. Refer > evlist__add_dummy_on_all_cpus(). > > So this could be handled by perf record.
Okay, I'll take a look at it and use this solution to deal with it.
Thanks, Yang
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