Messages in this thread | | | Date | Tue, 10 Jul 2012 17:38:40 -0600 | From | David Ahern <> | Subject | Re: perf with precise attribute kills all KVM based VMs |
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On 7/9/12 8:59 AM, Peter Zijlstra wrote: > 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. >
Any updates on the options for this or is there still squinting going on with MSR orders?
I guess it's a good thing Ingo's request for :pp to be the default was not implemented: https://lkml.org/lkml/2012/5/14/26
David
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