From: Arjan van de Ven Date: Tue, 22 Sep 2009 00:04:08 +0000 (-0700) Subject: cpuidle: fix the menu governor to boost IO performance X-Git-Tag: v2.6.32-rc1~456 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=69d25870f20c4b2563304f2b79c5300dd60a067e;p=pandora-kernel.git cpuidle: fix the menu governor to boost IO performance Fix the menu idle governor which balances power savings, energy efficiency and performance impact. The reason for a reworked governor is that there have been serious performance issues reported with the existing code on Nehalem server systems. To show this I'm sure Andrew wants to see benchmark results: (benchmark is "fio", "no cstates" is using "idle=poll") no cstates current linux new algorithm 1 disk 107 Mb/s 85 Mb/s 105 Mb/s 2 disks 215 Mb/s 123 Mb/s 209 Mb/s 12 disks 590 Mb/s 320 Mb/s 585 Mb/s In various power benchmark measurements, no degredation was found by our measurement&diagnostics team. Obviously a small percentage more power was used in the "fio" benchmark, due to the much higher performance. While it would be a novel idea to describe the new algorithm in this commit message, I cheaped out and described it in comments in the code instead. [changes since first post: spelling fixes from akpm, review feedback, folded menu-tng into menu.c] Signed-off-by: Arjan van de Ven Cc: Venkatesh Pallipadi Cc: Len Brown Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Yanmin Zhang Acked-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed