Messages in this thread | | | Date | Fri, 2 Mar 2012 14:23:03 -0800 | From | Andrew Morton <> | Subject | Re: Subject: [PATCH] cpuidle: Add a sysfs entry to disable specific C state for debug purpose. |
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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
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