From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Fri, 22 Jun 2012 13:52:09 +0000 (+0200)
Subject: sched/nohz: Rewrite and fix load-avg computation -- again
X-Git-Tag: v3.2.24~81
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d9a5888a4162d8e06eb909d31cbe5c779c8b67dc;p=pandora-kernel.git

sched/nohz: Rewrite and fix load-avg computation -- again

commit 5167e8d5417bf5c322a703d2927daec727ea40dd upstream.

Thanks to Charles Wang for spotting the defects in the current code:

 - If we go idle during the sample window -- after sampling, we get a
   negative bias because we can negate our own sample.

 - If we wake up during the sample window we get a positive bias
   because we push the sample to a known active period.

So rewrite the entire nohz load-avg muck once again, now adding
copious documentation to the code.

Reported-and-tested-by: Doug Smythies <dsmythies@telus.net>
Reported-and-tested-by: Charles Wang <muming.wq@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1340373782.18025.74.camel@twins
[ minor edits ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.2: adjust filenames, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

Reading git-diff-tree failed