On Fri, Jul 25, 2014 at 06:40:41PM +0200, Andi Kleen wrote: > > Suppose two pebs events, one has exclude_kernel set. It overflows, > > before entering the kernel, the other event generates PEBS records from > > inside the kernel with both events marked in the overflow field. > > > > And only once we leave the kernel can the exclude_kernel event tick > > again and trigger the assist, finalyl clearing the bit. > > > > If you were to report the records to both events, one would get a lot of > > kernel info he was not entitled to. > > Ok that case can be filtered in software. Shouldn't be too difficult. > Perhaps just using ip > > if (event->attr.exclude_kernel && pebs->ip >= __PAGE_OFFSET) > skip; > if (event->attr.exclude_user && pebs->ip < __PAGE_OFFSET) > skip; > > This would also help with the existing skid. > > Any other concerns?
Yeah, why fuck about and do ugly hacks when you can actually do it right? That way you're sure you've not forgotten anything.
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