Messages in this thread | | | Subject | Re: Subject: [PATCH] cpuidle: Add a sysfs entry to disable specific C state for debug purpose. | From | Yanmin Zhang <> | Date | Mon, 05 Mar 2012 09:34:31 +0800 |
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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.
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