From: Yanmin Zhang <yanmin_zhang@linux.intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Brown, Len" <len.brown@intel.com>,
"Liu, ShuoX" <shuox.liu@intel.com>, Ingo Molnar <mingo@elte.hu>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: Subject: [PATCH] cpuidle: Add a sysfs entry to disable specific C state for debug purpose.
Date: Mon, 05 Mar 2012 09:34:31 +0800 [thread overview]
Message-ID: <1330911271.1916.14.camel@ymzhang> (raw)
In-Reply-To: <20120302142303.648285a7.akpm@linux-foundation.org>
On Fri, 2012-03-02 at 14:23 -0800, Andrew Morton wrote:
> On Fri, 02 Mar 2012 08:17:33 +0800
> Yanmin Zhang <yanmin_zhang@linux.intel.com> wrote:
>
> > On Wed, 2012-02-29 at 04:55 +0000, Liu, ShuoX wrote:
> > > From: ShuoX Liu <shuox.liu@intel.com>
> > >
> > > Some C states of new CPU might be not good. One reason is BIOS might configure
> > > them incorrectly. To help developers root cause it quickly, the patch adds a
> > > new sysfs entry, so developers could disable specific C state manually.
> > >
> > > In addition, C state might have much impact on performance tuning, as it takes
> > > much time to enter/exit C states, which might delay interrupt processing. With
> > > the new debug option, developers could check if a deep C state could impact
> > > performance and how much impact it could cause.
> > >
> > > Signed-off-by: ShuoX Liu <shuox.liu@intel.com>
> > Andrew,
> >
> > Would you like to merge the patch into your testing tree?
>
> I can do that, but it's hardly my area and I can't comment on the
> desirability of the patch and Len is having quiet time. Perhaps the
> x86 guys can take a look please>
>
> > It's useful to help developers debug some issues.
>
> It would help developers more if it was documented a bit. As it
> stands, they'd be lucky if they even knew it existed.
>
> Looky:
>
> akpm:/usr/src/linux-3.3-rc5> grep -ril cpuidle Documentation
> Documentation/trace/events-power.txt
> Documentation/ABI/testing/sysfs-devices-system-cpu
> Documentation/kernel-parameters.txt
> Documentation/00-INDEX
> Documentation/cpuidle/core.txt
> Documentation/cpuidle/sysfs.txt
> Documentation/cpuidle/driver.txt
> Documentation/cpuidle/governor.txt
Thanks Andrew. We checked above document files. The best place to record
the new entry is Documentation/cpuidle/sysfs.txt. We would change it and
resend the patch.
next prev parent reply other threads:[~2012-03-05 1:35 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-29 4:55 Subject: [PATCH] cpuidle: Add a sysfs entry to disable specific C state for debug purpose Liu, ShuoX
2012-03-02 0:17 ` Yanmin Zhang
2012-03-02 22:23 ` Andrew Morton
2012-03-05 1:34 ` Yanmin Zhang [this message]
2012-03-05 3:22 ` Liu, ShuoX
2012-03-05 6:16 ` Deepthi Dharwar
2012-03-05 7:09 ` [PATCH V3] " ShuoX Liu
2012-03-05 10:18 ` Henrique de Moraes Holschuh
2012-03-05 12:20 ` [linux-pm] " Valentin, Eduardo
2012-03-06 1:54 ` Yanmin Zhang
2012-03-06 5:22 ` Greg KH
2012-03-06 5:51 ` Yanmin Zhang
2012-03-06 14:39 ` Greg KH
[not found] ` <1331082051.1916.124.camel@ymzhang>
[not found] ` <20120308180106.GD26516@kroah.com>
2012-03-12 9:19 ` [PATCH 1/3] cpuidle: Move cpuidle sysfs entry of each cpu to debugfs ShuoX Liu
2012-03-12 9:21 ` [PATCH 2/3] cpuidle: Add a debugfs entry to disable specific C state for debug purpose ShuoX Liu
2012-03-12 20:46 ` Matthew Garrett
2012-03-12 9:23 ` [PATCH 3/3] cpupower: Update the cpupower tool for new debugfs entries of cpuidle ShuoX Liu
2012-03-12 17:22 ` [PATCH 1/3] cpuidle: Move cpuidle sysfs entry of each cpu to debugfs Greg KH
2012-03-13 2:07 ` ShuoX Liu
2012-03-12 18:11 ` [linux-pm] [PATCH V3] cpuidle: Add a sysfs entry to disable specific C state for debug purpose Mark Brown
2012-03-12 19:29 ` Greg KH
2012-03-13 1:36 ` Yanmin Zhang
2012-03-13 19:29 ` Greg KH
2012-03-14 0:55 ` Yanmin Zhang
2012-03-14 2:46 ` Greg KH
2012-03-14 3:24 ` [linux-pm] [PATCH v4] " ShuoX Liu
2012-03-16 0:23 ` Yanmin Zhang
2012-03-16 21:33 ` Andrew Morton
2012-03-18 13:38 ` Henrique de Moraes Holschuh
2012-03-16 22:23 ` Andrew Morton
2012-03-06 1:04 ` [PATCH V3] " Yanmin Zhang
2012-03-13 0:42 ` Henrique de Moraes Holschuh
2012-03-13 1:18 ` Yanmin Zhang
2012-03-13 20:49 ` Henrique de Moraes Holschuh
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