From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Wanpeng Li <kernellwp@gmail.com>,
Paolo Bonzini <pbonzini@redhat.com>,
LKML <linux-kernel@vger.kernel.org>, kvm <kvm@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Marcelo Tosatti <mtosatti@redhat.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
KarimAllah <karahmed@amazon.de>,
Vincent Guittot <vincent.guittot@linaro.org>,
Ingo Molnar <mingo@kernel.org>,
Ankur Arora <ankur.a.arora@oracle.com>,
christopher.s.hall@intel.com, hubert.chrzaniuk@intel.com,
len.brown@intel.com, thomas.lendacky@amd.com
Subject: Re: [PATCH RFC] sched/fair: Penalty the cfs task which executes mwait/hlt
Date: Tue, 14 Jan 2020 23:46:18 +0100 [thread overview]
Message-ID: <1868711.0LYWRWiNKV@kreacher> (raw)
In-Reply-To: <20200113122911.GE2827@hirez.programming.kicks-ass.net>
On Monday, January 13, 2020 1:29:11 PM CET Peter Zijlstra wrote:
> On Mon, Jan 13, 2020 at 12:18:46PM +0100, Rafael J. Wysocki wrote:
> > On Monday, January 13, 2020 11:43:14 AM CET Peter Zijlstra wrote:
>
> > > Anyone, what will it take to get MPERF/TSC 'working' ?
> >
> > The same thing that intel_pstate does.
>
> But intel_pstate cheats, it has a FMS listing and possible 'interesting'
> chips are excluded. For instance, Core2 has APERF/MPERF, but
> intel_pstate does not support Core2.
>
> Simlarly, intel_pstate does (obviously) not support AMD chips, even tho
> those have APERF/MPERF.
>
> Although I suppose Core2 doesn't have VMX and is therefore less
> interesting, but then we'd need to gate the logic with something like:
>
> static_cpu_has(X86_FEATURE_APERFMPERF) &&
> (static_cpu_has(X86_FEATURE_VMX) || static_cpu_has(X86_FEATURE_SVM)
>
> > Generally speaking, it shifts the mperf values by a number of positions
> > depending on the CPU model, but that is 1 except for KNL.
> >
> > See get_target_pstate().
>
> I'm going to go out on a limb and guess that's the same KNL hack as
> TurboStat has.
>
> Is that really the only known case?
I'm not aware of any other at least as far as Intel chips go.
next prev parent reply other threads:[~2020-01-14 22:46 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-08 1:50 [PATCH RFC] sched/fair: Penalty the cfs task which executes mwait/hlt Wanpeng Li
2020-01-08 15:50 ` Peter Zijlstra
2020-01-08 17:14 ` Paolo Bonzini
2020-01-09 11:53 ` Wanpeng Li
2020-01-13 10:43 ` Peter Zijlstra
2020-01-13 11:18 ` Rafael J. Wysocki
2020-01-13 12:29 ` Peter Zijlstra
2020-01-14 22:46 ` Rafael J. Wysocki [this message]
2020-01-13 11:52 ` Paolo Bonzini
2020-01-13 12:35 ` Peter Zijlstra
2020-01-14 10:53 ` Wanpeng Li
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