From: Gleb Natapov <gleb@redhat.com>
To: Storm Wang <storm.whui@gmail.com>
Cc: kvm@vger.kernel.org
Subject: Re: use perf to get LLC-loads count in Guest
Date: Wed, 19 Dec 2012 17:47:34 +0200 [thread overview]
Message-ID: <20121219154734.GB17584@redhat.com> (raw)
In-Reply-To: <CADN=SKHCs-PCtMAfNm6iXCruq3u=JYUF0egydb9Ciq5+YtTOzA@mail.gmail.com>
On Wed, Dec 19, 2012 at 11:17:53PM +0800, Storm Wang wrote:
> >Currently counters that need extra regs are not supported by KVM PMU
> >emulation
> Thank you, Gleb. But actually only 1% chance, I got the LLC-loads
> count nonzero, I really have no idea why this happend.
>
May be without configuring MSR_OFFCORE_RSP_0 the counter still counts
something.
> On Wed, Dec 19, 2012 at 8:49 PM, Gleb Natapov <gleb@redhat.com> wrote:
> > On Wed, Dec 19, 2012 at 02:08:07AM +0800, Storm Wang wrote:
> >> Hello guys
> >>
> >> here I have a problem, when I used perf in Guest, the count of LLC-loads
> >> usually returns 0. LLC-loads was a hardware cache event, besides the
> >> setting of general PMU MSR, need to set MSR_OFFCORE_RSP_0 as well, in perf,
> >> it would be the extra_reg and extra_config in "hw_perf_event". I add some
> >> debuginfo in function "read_pmc" and found that when measuring LLC-loads,
> >> pmc->perf_event->hw.extra_reg is 0x0, and the counter's number was always
> >> the same. I think this is the reason, but I can't find when and where the
> >> value changed.
> >>
> >> Anybody has some idea for this?
> >>
> > Currently counters that need extra regs are not supported by KVM PMU
> > emulation.
> >
> > --
> > Gleb.
--
Gleb.
next prev parent reply other threads:[~2012-12-19 15:47 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CADN=SKGHgePSsVNkZZ566Ue-en37ica-MscPwffOw_TeZ5K0GQ@mail.gmail.com>
2012-12-19 12:49 ` use perf to get LLC-loads count in Guest Gleb Natapov
2012-12-19 15:17 ` Storm Wang
2012-12-19 15:47 ` Gleb Natapov [this message]
2012-12-19 4:26 Storm Wang
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