On Sun, 7 Aug 2005 00:54, Theodore Ts'o wrote: > On Tue, Aug 02, 2005 at 02:43:55PM +1000, Con Kolivas wrote: > > This is a code reordered version of the dynamic ticks patch from Tony > > Lindgen and Tuukka Tikkanen - sorry about spamming your mail boxes with > > this, but thanks for the code. There is significant renewed interest by > > the lkml audience for such a feature which is why I'm butchering your > > code (sorry again if you don't like me doing this). The only real > > difference between your code and this patch is moving the #ifdef'd code > > out of code paths and putting it into dyn-tick specific files. > > > > This has slightly more build fixes than the last one I posted and boots > > and runs fine on my laptop. So far at absolute idle it appears this > > pentiumM 1.7 is claiming to have _25%_ more battery life. I'll need to > > investigate further to see the real power savings. > > Hi Con, > > I had a chance to try out your patch (2.6.13-rc4-dtck-2.patch) and > using either the APIC or PIT timer, if dynamic tick is enabled, on my > laptop, this kicks up the bus mastering activity enough so that the > processor doesn't have a chance to enter the C4 state, and stays stuck > at C2. As a result, enabling dynamic tick _increases_ power > consumption by 20% on my T40 laptop (1.6 MHz Pentium M).
Lovely! (not) > I monitored > power utilization using pmstats-0.2, and used > /proc/acpi/processor/CPU/power to monitor bus mastering activity and the > CPU C-states. > > As soon as I disabled dynamic tick using: > > echo 0 > /sys/devices/system/timer/timer0/dyn_tick_state > > The number of ticks went up to 1024, bus mastering activity dropped to > zero, and the processor entered C4 state, and power utilization > dropped by 20%. > > When I enabled dynamic tick using: > > echo 1 > /sys/devices/system/timer/timer0/dyn_tick_state > > The number of ticks dropped down to 60-70 HZ, bus mastering activity > jumpped up to being almost always active, Anyone know why this would happen? > and the processor stayed > stuck at C2 state, and power utilization climbed back up by 20%. > > This was on a completely idle, freshly booted machine, without X > running and just a console login. Thanks for testing. Cheers, Con - 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/
