From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754860AbXLHF2u (ORCPT ); Sat, 8 Dec 2007 00:28:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752117AbXLHF2m (ORCPT ); Sat, 8 Dec 2007 00:28:42 -0500 Received: from qmta05.westchester.pa.mail.comcast.net ([76.96.62.48]:37902 "EHLO QMTA05.westchester.pa.mail.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751542AbXLHF2l (ORCPT ); Sat, 8 Dec 2007 00:28:41 -0500 X-Authority-Analysis: v=1.0 c=1 a=Sv6w6hjq99wA:10 a=8VcNbOb3AAAA:8 a=BcU4Fu6L959vHpTdt40A:9 a=GfthskL2n4pX9fv5YQ13lGZnu4oA:4 a=tXPUrm4B3N8A:10 Message-ID: <475A2B87.9090800@comcast.net> Date: Sat, 08 Dec 2007 00:28:39 -0500 From: Ed Sweetman User-Agent: Mozilla-Thunderbird 2.0.0.6 (X11/20071008) MIME-Version: 1.0 To: Robert Hancock CC: linux-kernel@vger.kernel.org Subject: Re: x86_64 dynticks not working prev: cpuidle, dynticks compatible or no? References: <475A148C.50100@shaw.ca> <475A23E0.90500@comcast.net> In-Reply-To: <475A23E0.90500@comcast.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ed Sweetman wrote: > Robert Hancock wrote: >> Ed Sweetman wrote: >>> System is idle now, previously it was doing something i couldn't >>> halt at the time. I'm looking at "Local timer interrupts" in the >>> "Loc:" section of /proc/interrupts. >>> Across 1 second while the system is pretty much idle, i still get >>> 300 interrupts. My HZ variable is set to 300 in the kernel config, >>> so this is expected but I was under the assumption that >>> dynticks/tickless being compiled in would cause that to be much lower. >>> >>> Am I reading the wrong section of /proc/interrupts to verify if >>> dynticks is working or not? Again, i see no difference in cpu temp >>> at all. >> >> Try running powertop ( http://www.lesswatts.org/projects/powertop/ ) >> and see what it reports. >> >> I don't think dynticks will generally save huge amounts of power on a >> typical desktop machine. The big gains come from being able to stay >> in deep sleep C-states (C2/C3) for longer periods of time, but most >> desktop machines only enable sleep states down to C1. >> > I tried running powertop, it complains about not having timer > statistics, I looked throughout the kernel config for a timer stat > option, but can't find one. > > I didn't have hpet compiled in, i'm not sure if this is required but a > lot of places seem to suggest hpet and high precision timer and > tickless be compiled together. I also disabled cpuidle and i'll > reboot and try that. > read too fast through the powertop error message. timer stat info is in kernel_debug option. Which i did not compile in this latest kernel again. Sorry. Though, with hpet and such, i still see no measurable difference or any sort of evidence that ticks are being skipped (comparing /proc/interrupts across sleep 1s;) > >>> >>> In case it helps, this is an athlon64 x2 with apic functioning and >>> both cores active in 64bit mode. dmesg is below. >>> not related : >>> Some additional notes: it87 is my lm_sensor, it doesn't work in >>> this kernel, yet it did in 2.6.22. Perhaps enabling high precision >>> timers changed something in acpi land. >>> >>> I enabled tcp dma offloading in this kernel, i get debugging output >>> related to it, error is at the last line. No corruption or >>> otherwise bad behavior. Transferring via cifs at 9.7MB/sec >>> "incoming" took about 15% of one cpu... I never bothered to check >>> if that is the norm but i suspect i'll be removing that feature as >>> it seems to not play nice with the kernel. >> >