Re: [RESEND PATCH V3 3/8] perf/x86/intel: Support hardware TopDown metrics

From: Peter Zijlstra
Date: Wed Aug 28 2019 - 12:29:05 EST


On Wed, Aug 28, 2019 at 09:17:54AM -0700, Andi Kleen wrote:
> > This really doesn't make sense to me; if you set FIXED_CTR3 := 0, you'll
> > never trigger the overflow there; this then seems to suggest the actual
>
> The 48bit counter might overflow in a few hours.

Sure; the point is? Kan said it should not be too big; a full 48bit wrap
around must be too big or nothing is.