linux-kernel - Re: [PATCH] X86/CPU: Avoid 100ms sleep for cpu offline during S3

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Message-ID: <20140806160652.GD27033@pd.tnic>
Date:	Wed, 6 Aug 2014 18:06:52 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	"Lan, Tianyu" <tianyu.lan@...el.com>
Cc:	"tglx@...utronix.de" <tglx@...utronix.de>,
	"mingo@...hat.com" <mingo@...hat.com>,
	"hpa@...or.com" <hpa@...or.com>, "x86@...nel.org" <x86@...nel.org>,
	"toshi.kani@...com" <toshi.kani@...com>,
	"imammedo@...hat.com" <imammedo@...hat.com>,
	"jan.kiszka@...mens.com" <jan.kiszka@...mens.com>,
	"mingo@...nel.org" <mingo@...nel.org>,
	"huawei.libin@...wei.com" <huawei.libin@...wei.com>,
	"prarit@...hat.com" <prarit@...hat.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Brandt, Todd E" <todd.e.brandt@...el.com>
Subject: Re: [PATCH] X86/CPU: Avoid 100ms sleep for cpu offline  during S3

Hi,

On Wed, Aug 06, 2014 at 01:13:21PM +0000, Lan, Tianyu wrote:
> Have you tried my attached kernel config file? When someone reported
> the issue to me, I also was very hard to reproduce the issue by my
> own config file. Maybe once 100 tries. But I can reproduced the issue
> every time with the attached configure file on several my machines and
> even on server.

first of all, please do not top-post:

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

Now, it looks like the issue is timing-related, depending on when we're
going to see CPU_DEAD, before or after the msleep. Thus, if some distro
config runs more crap on the suspend path and we don't see the CPU_DEAD
before we sleep for 100ms, then we get to wait at least once and it
shows in the suspend trace.

So, using the completion timeout seems like a net improvement for such
configs and thus for any config.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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