linux-kernel - Re: cputime takes cstate into consideration

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Message-ID: <alpine.DEB.2.21.1906262119430.32342@nanos.tec.linutronix.de>
Date:   Wed, 26 Jun 2019 21:23:10 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     "Raslan, KarimAllah" <karahmed@...zon.de>
cc:     "boris.ostrovsky@...cle.com" <boris.ostrovsky@...cle.com>,
        "joao.m.martins@...cle.com" <joao.m.martins@...cle.com>,
        "konrad.wilk@...cle.com" <konrad.wilk@...cle.com>,
        "ankur.a.arora@...cle.com" <ankur.a.arora@...cle.com>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "rkrcmar@...hat.com" <rkrcmar@...hat.com>,
        "pbonzini@...hat.com" <pbonzini@...hat.com>,
        "kernellwp@...il.com" <kernellwp@...il.com>,
        "mtosatti@...hat.com" <mtosatti@...hat.com>
Subject: Re: cputime takes cstate into consideration

On Wed, 26 Jun 2019, Raslan, KarimAllah wrote:
> On Wed, 2019-06-26 at 10:54 -0400, Konrad Rzeszutek Wilk wrote:
> > There were some ideas that Ankur (CC-ed) mentioned to me of using the perf
> > counters (in the host) to sample the guest and construct a better
> > accounting idea of what the guest does. That way the dashboard
> > from the host would not show 100% CPU utilization.
> 
> You can either use the UNHALTED cycles perf-counter or you can use MPERF/APERF 
> MSRs for that. (sorry I got distracted and forgot to send the patch)

Sure, but then you conflict with the other people who fight tooth and nail
over every single performance counter.

Thanks,

	tglx