Messages in this thread | | | Date | Tue, 24 Oct 2017 11:22:00 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH V3 0/6] event synthesization multithreading for perf record |
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* Liang, Kan <kan.liang@intel.com> wrote:
> For 'all', do you mean the whole process?
Yeah.
> I think that's the ultimate goal. Eventually there will be per-CPU recording > threads created at the beginning of perf record and go through the whole process. > The plan is to do the multithreading step by step from the simplest case. > Synthesizing stage is just a start.
So, why not do it like the kernel did: add all the threads, create the percpu files, and introduce a 'big perf lock' (big mutex) that is taken for all the current non-threaded perf functionality. This should be fairly straightforward to do and should be 'obviously correct'.
_Then_ start doing the hard threading work on top of this, like threading the synthesizing phase.
Doing the whole per CPU thread setup/teardown for just the synthesizing part of it looks like the wrong design.
I.e. what I'm suggesting is no extra threading work, just organizing it in a different fashion and increasing the life-time of the per CPU threads from 'perf startup' to 'perf shutdown'.
Thanks,
Ingo
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