linux-kernel - Re: ACPI _CST introduced performance regresions on Haswll

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Date:   Wed, 7 Oct 2020 20:23:09 +0100
From:   Mel Gorman <mgorman@...hsingularity.net>
To:     "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Cc:     Takashi Iwai <tiwai@...e.de>, linux-kernel@...r.kernel.org
Subject: Re: ACPI _CST introduced performance regresions on Haswll

On Wed, Oct 07, 2020 at 05:40:43PM +0200, Rafael J. Wysocki wrote:
> > # grep . enable-cst/cpuidle/state*/disable
> > enable-cst/cpuidle/state0/disable:0
> > enable-cst/cpuidle/state1/disable:0
> > enable-cst/cpuidle/state2/disable:0
> > enable-cst/cpuidle/state3/disable:1
> > enable-cst/cpuidle/state4/disable:1
> > # grep . enable-cst/cpuidle/state*/default_status
> > enable-cst/cpuidle/state0/default_status:enabled
> > enable-cst/cpuidle/state1/default_status:enabled
> > enable-cst/cpuidle/state2/default_status:enabled
> > enable-cst/cpuidle/state3/default_status:disabled
> > enable-cst/cpuidle/state4/default_status:disabled
> > 
> > That looks like C3 and C6 are disabled after the patch.
> > 
> > # grep . enable-cst/cpuidle/state*/name
> > enable-cst/cpuidle/state0/name:POLL
> > enable-cst/cpuidle/state1/name:C1
> > enable-cst/cpuidle/state2/name:C1E
> > enable-cst/cpuidle/state3/name:C3
> > enable-cst/cpuidle/state4/name:C6
> > 
>
> That's kind of unexpected and there may be two reasons for that.
> 
> First off, the MWAIT hints in the ACPI tables for C3 and C6 may be different
> from the ones in the intel_idle internal table.
> 
> Second, the ACPI tables may only be listing C1.
> 
> Can you send me the acpidump output from the affected machine, please?
> 

Attached.

Thanks.

-- 
Mel Gorman
SUSE Labs

Download attachment "acpidump.xz" of type "application/x-xz" (92724 bytes)