Messages in this thread | | | Subject | Re: perf with precise attribute kills all KVM based VMs | From | Peter Zijlstra <> | Date | Mon, 09 Jul 2012 16:59:59 +0200 |
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On Mon, 2012-07-09 at 17:51 +0300, Avi Kivity wrote: > On 07/09/2012 05:49 PM, Peter Zijlstra wrote: > > On Mon, 2012-07-09 at 08:47 -0600, David Ahern wrote: > >> > >> I found this testing changes to perf-kvm, but found the problem extends > >> to just perf-record. With perf-record exclude_guest defaults to 1. See > >> tools/perf/util/util.c, event_attr_init(). > > > > You lost me there.. so perf-record defaults to exclude_guest=1 (which > > would make the proposed patch I just send actually possible), but its > > still going *bang* ? > > It's possible that the DS writes overshoot the MSR... or that there's a > bug somewhere.
OK, so the first thing to stare at is in what order the MSRs are touched, I think you first need to stop the counter, then clear the PEBS bits, then clear the DS_AREA one.
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