Messages in this thread | | | Date | Mon, 11 May 2015 09:43:41 -0700 | Subject | Re: [PATCH 9/9] x86, perf: Move PMU ACK after LBR read | From | Stephane Eranian <> |
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On Mon, May 11, 2015 at 9:36 AM, Peter Zijlstra <peterz@infradead.org> wrote: > On Mon, May 11, 2015 at 09:32:33AM -0700, Stephane Eranian wrote: >> >> This is a minimal change. In principle the ACK could be moved much later. >> > >> > Right, so the more complete change would be to use the new and improved >> > FREEZE_ON_PMI and reenable both the LBRs and the CTRs with the >> > STATUS_RESET MSR, right? >> > >> > Does it make sense to have a new handle_irq() routine for that? >> >> Were we not already using FREEZE_ON_PMI with LBR (except for one >> erratum on HSW)? > > That's FREEZE_LBRS_ON_PMI, I was referring to FREEZE_PERFMON_ON_PMI, > which we've not used so far. > Ah, yes that one was not used so far. I don't quite remember why. I think with PEBS, you don't need it or it should be off or something like this.
> I think Andi tried using it before, but there's some issues with it on > v3, but v4 should have fixed all that. > I was referring to a LBR issue on v3 (HSW) and call stack mode.
> Andi can you perhaps explain what the problem with FREEZE_PERFMON_ON_PMI > on v3 was again? > Andi, Is that what I am alluding to above?
>> It would make sense to me to have an "optimized" and clean handle_irq >> for the newer PMU. >> We the caveat that any change to the core of it would now have to be done twice. > > We could pull that out in a shared function of course, if possible.
Good.
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