Messages in this thread | | | Date | Fri, 11 Dec 2015 17:01:36 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v0 3/5] perf: Introduce instruction trace filtering |
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On Fri, Dec 11, 2015 at 05:48:03PM +0200, Alexander Shishkin wrote:
> > We can always call the validation thing, we must not call the program > > thing !ACTIVE is a clear and simple rule. > > Ah, but pmu::itrace_filter_setup() does not touch the hardware, > pmu::start() does. The former keeps an array of, say, MSR values ready > for programming in event::hw and the latter actually writes the MSRs. So > the above example should not be a problem. > > So in a way validation and programming are split already. And PT, for > example, won't have it any other way, you can only program stuff into > the registers while tracing is disabled.
Yes, I just read that in the last patch. If however we fold the whole stop/start bits into it, that fails again.
Hmm.. lemme ponder a bit.
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