Messages in this thread | | | Subject | Re: Too many poll_idle cpu calls in kernel 3.2 rc-series | From | Mike Galbraith <> | Date | Sat, 10 Dec 2011 08:33:25 +0100 |
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On Tue, 2011-11-29 at 16:37 +0530, Deepthi Dharwar wrote: > On 11/29/2011 02:14 AM, Andi Kleen wrote: > > > On Mon, Nov 28, 2011 at 09:31:13PM +0100, Nicolas Kalkhof wrote: > >> Andi, > >> > >> correct. The issue was introduced somewhere between 3.1 final and 3.2-rc1. I've tried to track down the bad commit but so far I haven't been successfull. The only workaround I found is to set the idle boot parameter to mwait and to disable CONFIG_INTEL_IDLE. Somehow the kernel seems to set idle to poll by default - no idea why :-(. I wonder if other mobile sandy bridge cpus are affected as well. > > > > There are only a few changesets affecting drivers/idle > > > > Can you try to git revert > > > > 46bcfad7a819bd17ac4e831b04405152d59784ab > > 4202735e8ab6ecfb0381631a0d0b58fefe0bd4e2 > > e978aa7d7d57d04eb5f88a7507c4fb98577def77 > > > > ? > > > > -Andi > > > Hi, > > I am guessing that for workaround just setting the idle boot parameter > to mwait should work. Have u tested this without disabling > CONFIG_INTEL_IDLE ? > > Also one thing to note from your logs is, cpu is not entering any of the > other C states except for POLL. Can you also check if your are enabling > only POLL for idle. I am able to enter deeper C-states on i5-2540M with > Intel_Idle enabled.
Seems I accidentally found a way to reproduce, boot with nohz=off. Q6600 box can be booted nohz=off without ending up as if I'd booted idle=poll, but boxen using intel_idle() end up using poll_idle().
-Mike
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