From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Seyfried Subject: Re: Help! I lost my C4 states :-) Date: Fri, 4 Mar 2005 18:05:53 +0100 Message-ID: <20050304170553.GA28717@message-id.s3e.de> References: <20050221081225.GA10848@message-id.gmane0305.slipkontur.de> <1109885929.2103.813.camel@d845pe> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1109885929.2103.813.camel@d845pe> Sender: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Len Brown Cc: Stefan Seyfried , ACPI Developers , Dominik Brodowski List-Id: linux-acpi@vger.kernel.org On Thu, Mar 03, 2005 at 04:38:49PM -0500, Len Brown wrote: > On Mon, 2005-02-21 at 03:12, Stefan Seyfried wrote: > > Any hints on how to track down what is causing bus master activity all the > > time? > > Has the calculation algorithm changed? Any default settings i could tweak? > > Did you notice a battery life decrease with this decrease in C4 > residency? Yes, although i lately run the battery down only on rare occasions, but the "projected" runtime with mostly C4 active was almost 4 hours while now it is a bit more than 3h30. I do no longer spin down the disk, since my dell locks up hard sometimes when the disk should spin up again, but the C4 was at least as big a gain than doing really aggressive disk spindown, (including laptop_mode etc, my disk was _really_ spun down for 10 minutes between short spinups). In fact, i noticed that C4 started working since i noticed that my battery started to last longer. When i still spun down the disk, this was hardly noticeable. > On January 20th we pushed Dominik's jiffies based bm_activity patch > in drivers/acpi/processor_idle.c You might find that backing out > that file a couple of revisions restores the previous behaviour. > > Just after that, I added a tunable that you can tweak -- > with 1000 HZ, its default is all bits enabled, but > you can reduce this bit mask to make the driver > ignore less recent history: > > # echo 0 > /sys/module/processor/parameters/bm_history > > Will cause the processor driver to ignore the bus master activity > completely. Note that this could cause a performance hit if > there is BM activity since will just pop the system out of C4 > and no instructions are executed during the transition out of C4. I tried fiddling with this parameter, but will try again. I think i never set it to zero, only 0xffff or something like that. > > cheers, > -Len > > ps. > If you're tracking battery life, I'd be interested to know if > you notice a difference between when you build with HZ=100 and HZ=1000. I'll do it as soon as Andrea Arcangely puts back the "select HZ Patch" back into the SUSE kernel. Unfortunately i mostly have to run stock compiled kernels just to be able to file "valid" bugreports :-) -- Stefan Seyfried ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click