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From: "Fontenot, Nathan" <Nathan.Fontenot@amd.com>
To: Tom Lendacky <thomas.lendacky@amd.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Giovanni Gherdovich <ggherdovich@suse.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Mel Gorman <mgorman@suse.de>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Julia Lawall <julia.lawall@inria.fr>,
	Ingo Molnar <mingo@redhat.com>,
	kernel-janitors@vger.kernel.org,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	linux-kernel@vger.kernel.org,
	Valentin Schneider <valentin.schneider@arm.com>,
	Gilles Muller <Gilles.Muller@inria.fr>,
	srinivas.pandruvada@linux.intel.com,
	Linux PM <linux-pm@vger.kernel.org>,
	Len Brown <len.brown@intel.com>,
	puwen@hygon.cn, yazen.ghannam@amd.com, kim.phillips@amd.com,
	suravee.suthikulpanit@amd.com
Subject: Re: default cpufreq gov, was: [PATCH] sched/fair: check for idle core
Date: Mon, 26 Oct 2020 19:52:37 +0000	[thread overview]
Message-ID: <0a3abadf-181e-99dd-1304-86a34505dfe8@amd.com> (raw)
In-Reply-To: <4a0db95a-1ba2-21f5-5c9d-67b9f82ed130@amd.com>

On 10/23/2020 12:46 PM, Tom Lendacky wrote:
> On 10/23/20 2:03 AM, Peter Zijlstra wrote:
>> On Thu, Oct 22, 2020 at 10:10:35PM +0200, Giovanni Gherdovich wrote:
>>> * for the AMD EPYC machines we haven't yet implemented frequency invariant
>>>    accounting, which might explain why schedutil looses to ondemand on all
>>>    the benchmarks.
>>
>> Right, I poked the AMD people on that a few times, but nothing seems to
>> be forthcoming :/ Tom, any way you could perhaps expedite the matter?
> 
> Adding Nathan to the thread to help out here.
> 
> Thanks,
> Tom

Thanks Tom, diving in...

> 
>>
>> In particular we're looking for some X86_VENDOR_AMD/HYGON code to run in
>>
>>    arch/x86/kernel/smpboot.c:init_freq_invariance()
>>
>> The main issue is finding a 'max' frequency that is not the absolute max
>> turbo boost (this could result in not reaching it very often) but also
>> not too low such that we're always clipping.

I've started looking into this and have a lead but need to confirm that the
frequency value I'm getting is not an absolute max.

>>
>> And while we're here, IIUC AMD is still using acpi_cpufreq, but AFAIK
>> the chips have a CPPC interface which could be used instead. Is there
>> any progress on that?
>>

Correct, AMD uses acpi_cpufreq. The newer AMD chips do have a CPPC interface
(not sure how far back 'newer' covers). I'll take a look at schedutil and
cppc_cpufreq and the possibility of transitioning to them for AMD.

-Nathan

  reply	other threads:[~2020-10-26 19:52 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-20 16:37 [PATCH] sched/fair: check for idle core Julia Lawall
2020-10-21  7:29 ` Vincent Guittot
2020-10-21 11:13   ` Peter Zijlstra
2020-10-21 12:27   ` Vincent Guittot
2020-10-21 11:20 ` Mel Gorman
2020-10-21 11:56   ` Julia Lawall
2020-10-21 12:19     ` Peter Zijlstra
2020-10-21 12:42       ` Julia Lawall
2020-10-21 12:52         ` Peter Zijlstra
2020-10-21 18:18           ` Rafael J. Wysocki
2020-10-21 18:15         ` Rafael J. Wysocki
2020-10-21 19:47           ` Julia Lawall
2020-10-21 20:25             ` Rafael J. Wysocki
2020-10-21 13:10       ` Peter Zijlstra
2020-10-21 18:11         ` Rafael J. Wysocki
2020-10-22  4:53           ` Viresh Kumar
2020-10-22  7:11           ` Peter Zijlstra
2020-10-22 10:59             ` Viresh Kumar
2020-10-22 11:45               ` Rafael J. Wysocki
2020-10-22 12:02                 ` default cpufreq gov, was: " Peter Zijlstra
2020-10-22 12:19                   ` Rafael J. Wysocki
2020-10-22 12:29                     ` Peter Zijlstra
2020-10-22 14:52                       ` Mel Gorman
2020-10-22 14:58                         ` Colin Ian King
2020-10-22 15:12                           ` Phil Auld
2020-10-22 16:35                             ` Mel Gorman
2020-10-22 17:59                               ` Rafael J. Wysocki
2020-10-22 20:32                                 ` Mel Gorman
2020-10-22 20:39                                   ` Phil Auld
2020-10-22 15:25                         ` Peter Zijlstra
2020-10-22 15:55                           ` Rafael J. Wysocki
2020-10-22 16:29                           ` Mel Gorman
2020-10-22 20:10                           ` Giovanni Gherdovich
2020-10-22 20:16                             ` Giovanni Gherdovich
2020-10-23  7:03                             ` Peter Zijlstra
2020-10-23 17:46                               ` Tom Lendacky
2020-10-26 19:52                                 ` Fontenot, Nathan [this message]
2020-10-22 15:45                       ` A L
2020-10-22 15:55                         ` Vincent Guittot
2020-10-23  5:23                           ` Viresh Kumar
2020-10-22 16:23                   ` [PATCH] cpufreq: Avoid configuring old governors as default with intel_pstate Rafael J. Wysocki
2020-10-23  6:29                     ` Viresh Kumar
2020-10-23 11:59                       ` Rafael J. Wysocki
2020-10-23 15:15                     ` [PATCH v2] " Rafael J. Wysocki
2020-10-27  3:13                       ` Viresh Kumar
2020-10-27 11:11                   ` default cpufreq gov, was: [PATCH] sched/fair: check for idle core Qais Yousef
2020-10-27 11:26                     ` Valentin Schneider
2020-10-27 11:42                       ` Qais Yousef
2020-10-27 11:48                         ` Viresh Kumar
2020-10-23  6:24                 ` Viresh Kumar
2020-10-23 15:06                   ` Rafael J. Wysocki
2020-10-27  3:13                     ` Viresh Kumar
2020-10-22 11:21             ` AW: " Walter Harms
2020-10-21 12:28     ` Mel Gorman
2020-10-21 12:25   ` Vincent Guittot
2020-10-21 12:47     ` Mel Gorman
2020-10-21 12:56       ` Julia Lawall
2020-10-21 13:18         ` Mel Gorman
2020-10-21 13:24           ` Julia Lawall
2020-10-21 15:08             ` Mel Gorman
2020-10-21 15:18               ` Julia Lawall
2020-10-21 15:23                 ` Vincent Guittot
2020-10-21 15:33                   ` Julia Lawall
2020-10-21 15:19               ` Vincent Guittot
2020-10-21 17:00                 ` Mel Gorman
2020-10-21 17:39                   ` Julia Lawall
2020-10-21 13:48           ` Julia Lawall
2020-10-21 15:26             ` Mel Gorman

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