Messages in this thread | | | Subject | Re: [PATCH 7/9] ftrace, perf: Add support to use function tracepoint in perf | From | Peter Zijlstra <> | Date | Mon, 28 Nov 2011 21:18:10 +0100 |
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On Mon, 2011-11-28 at 15:16 -0500, Steven Rostedt wrote: > On Mon, 2011-11-28 at 21:10 +0100, Peter Zijlstra wrote: > > > > Yeah, but still not something you want to do during context switches, > > > right? > > > > Also, that's x86, there's still archs that need stop_machine(), right? > > s390 may need it, but till we add a work around there too. > > But yeah, if this happens at context switch, then we want the fast > enable/disable that Jiri made.
Right, so the way tracepoint->perf works currently is we enable the tracepoint when we create the event. The tracepoint handler runs a per-cpu hlist. perf then registers with the per-cpu hlist on context switch.
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