Re: [PATCH 6/6] x86: Allow disabling HW_BREAKPOINTS and PERF_EVENTS

From: Ingo Molnar
Date: Wed Oct 09 2013 - 02:02:38 EST



* Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote:

> On Tue, Oct 08, 2013 at 10:05:21PM +0200, Peter Zijlstra wrote:
> > On Tue, Oct 08, 2013 at 09:55:59PM +0200, Frederic Weisbecker wrote:
> > > 1) make breakpoints independant from perf. The drawback is that we must then
> > > add seperate hooks on context switch for ptrace breakpoints. OTOH we get
> > > rid of the perf -> breakpoint -> perf circular dependency, which is the very
> > > controversial thing.
> >
> > we used to have this in __switch_to_xtra(), right?
>
> Right.
>
> And then it got replaced by perf events scheduling.

Which we have anyway - so this moved complexity out the contex switch
path, for the common case where no hardware-breakpoints are used.

Thanks,

Ingo
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