Re: [PATCH 7/9] ftrace, perf: Add support to use functiontracepoint in perf

[Peter Zijlstra]

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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