Messages in this thread | | | Date | Fri, 22 Dec 2006 02:06:41 +0100 | From | Adrian Bunk <> | Subject | Re: [PATCH] add i386 idle notifier (take 3) |
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On Thu, Dec 21, 2006 at 01:12:42AM -0800, Stephane Eranian wrote: > Andrew, > > On Wed, Dec 20, 2006 at 09:05:14PM -0800, Andrew Morton wrote: > > On Wed, 20 Dec 2006 06:05:00 -0800 > > Stephane Eranian <eranian@hpl.hp.com> wrote: > > > > > Hello, > > > > > > Here is the latest version of the idle notifier for i386. > > > This patch is against 2.6.20-rc1 (GIT). In this kernel, the idle > > > loop code was modified such that the lowest level idle > > > routines do not have loops anymore (e.g., poll_idle). As such, > > > we do not need to call enter_idle() in all the interrupt handlers. > > > > > > This patch also duplicates the x86-64 bug fix for a race condition > > > as posted by Venkatesh Pallipadi from Intel. > > > > > > changelog: > > > - add idle notification mechanism to i386 > > > > > > > None of the above text is actually usable as a changelog entry. We are > > left wondering: > > > > - why is this patch needed? > > > > - what does it do? > > > > - how does it do it? > > > > The three questions which all changelogs should answer ;) > > Sorry about that. Here is a new changelog: > > changelog: > - add a notifier mechanism to the low level idle loop. You can > register a callback function which gets invoked on entry and exit > from the low level idle loop. The low level idle loop is defined as > the polling loop, low-power call, or the mwait instruction. Interrupts > processed by the idle thread are not considered part of the low level > loop. The notifier can be used to measure precisely how much is spent > in useless execution (or low power mode). The perfmon subsystem uses it > to turn on/off monitoring.
Why is this patch not submitted as part of the perfmon patch that also adds a user of this code?
And why does it bloat the kernel with EXPORT_SYMBOL's although even your perfmon-new-base-061204 doesn't seem to add any modular user?
> -Stephane
cu Adrian
--
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