>-----Original Message----- >From: Björn Steinbrink [mailto:[EMAIL PROTECTED] >Sent: Monday, May 21, 2007 12:50 AM >To: Andi Kleen >Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED]; Zhu, Yi; >linux-kernel@vger.kernel.org; [EMAIL PROTECTED]; Pallipadi, >Venkatesh; [EMAIL PROTECTED] >Subject: Re: Increased ipw2200 power usage with dynticks > >On 2007.05.20 20:55:35 +0200, Andi Kleen wrote: >> Björn Steinbrink <[EMAIL PROTECTED]> writes: >> > >> > Ok, it seems that ipw2200 is just a trigger for the >problem here. AFAICT >> > the cause of the worse C state usage is that after ipw2200 >has woken the >> > cpu, acpi_processor_idle() chooses C2 (due to dma? bm? I have no >> > idea...) as the prefered sleep state. Now without NO_HZ or >when I hold >> > down a key, there are interrupts that wake up the CPU and when >> > acpi_processor_idle() is called again the promotion to >C3/C4 happens. >> > But with NO_HZ, there are no such interrupts, most wakeups >are caused by >> > ipw2200 and so the processor doesn't go any deeper than C2 >most of the >> > time and thus wastes lots of power. >> >> The cpuidle governour code Venki is working on is supposed >to address this. >> There have been also earlier prototype patches by Adam Belay and >> Thomas Renninger. > >Venki (at least I think it was him) also told me about cpuidle and the >menu governor on #powertop. Unfortunately, cpuidle seems to be >gone from >acpi-test (or I'm simply still too stupid for git/gitweb). I manually >added the cpuidle and menu governor patches on top of my >2.6.22-rc1-hrt8 >kernel, but that broke C-state duration accounting. > >On the bright side of things is power usage though, which is down to an >incredible 13.9W in idle+ipw2200 :) >
Nice to hear that cpuidle-menu governor gets 13.9W :-). Powertop will need some changes to go with cpuidle, but that should be simple. We need some more testing for cpuidle before it gets into git. Len: Looks like cpuidle got dropped out of mm again. Can you merge it back it please. Thanks, Venki - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
