linux-kernel - Re: [PATCH 3/3][RFC/RFT] PM / sleep: Do not delay the synchronization of MTRR during resume

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Date:   Tue, 6 Feb 2018 15:04:17 +0100
From:   Lukas Wunner <lukas@...ner.de>
To:     Yu Chen <yu.c.chen@...el.com>
Cc:     x86@...nel.org, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Len Brown <len.brown@...el.com>, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Rui Zhang <rui.zhang@...el.com>
Subject: Re: [PATCH 3/3][RFC/RFT] PM / sleep: Do not delay the
 synchronization of MTRR during resume

On Thu, Dec 14, 2017 at 12:02:42AM +0800, Yu Chen wrote:
> On Wed, Dec 13, 2017 at 01:31:50AM +0100, Rafael J. Wysocki wrote:
> > On Tuesday, October 31, 2017 10:58:50 AM CET Yu Chen wrote:
[snip]
> > > In one word, with the patch applied, the cpu online time during resume
> > > has decreased by about 6 seconds on a bogus MTRR platform, and decreased
> > > by about 600ms on a 88 cpus Xeon platform after resumed.
> > > 
> > > Cc: Len Brown <len.brown@...el.com>
> > > Cc: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > > Cc: Rui Zhang <rui.zhang@...el.com>
> > > Signed-off-by: Chen Yu <yu.c.chen@...el.com>
> > 
> > It will be better to combine this with patch [2/3] IMO, because that makes
> > it clear why the changes in that patch are needed.
> > 
> > Also you can define the new flag in mtrr/main.c, set it in
> > arch_enable_nonboot_cpus_begin() and clear it in
> > arch_enable_nonboot_cpus_end().  It is better to put it into the
> > arch-specific code as the flag itself is arch-specific.
> > 
> > Then, of course, you don't need patch [1/3] and all can be done in one
> >  patch.
> 
> Ok, will rewrite the patch, thanks! 

Just for the record, this series cuts down resume time from system sleep
by 4-5 seconds on my MacBookPro9,1.  Great work, looking forward to this
being respun and merged.

Tested-by: Lukas Wunner <lukas@...ner.de>

Thanks,

Lukas