Mark Hellman wrote:
Thomas Renninger wrote:That's very interessting. Could you please compare the supported C-states on the machines. I bet it is related to those.I have just installed 10.0-beta4 on the Pentium-M laptop and I noticed that something seems to have gotten a little bit worse. Before, when Powersave scheme was enabled, the processor was mainly on C3. Now it almost never leaves C2, according to /proc/acpi/processor/CPU0/power:active state: C2 max_cstate: C8 bus master activity: 11108888 states: C1: type[C1] promotion[C2] demotion[--] latency[001] usage[00000010] *C2: type[C2] promotion[C3] demotion[C1] latency[001] usage[01143473] C3: type[C3] promotion[--] demotion[C2] latency[085] usage[00000019]speedstep_centrino module is loaded on the Pentium-M machine. The Celeron laptop never enters C3, but this doesn't seem to influence the battery life (which is the same as in Windows).
Ok, I am quite sure it's C3 that gives your Pentium M that much more battery life time.
Please also have a look at "cat /proc/sys/kernel/HZ".On both system its 1000 Hz. Doesn't the 'desktop' kernel parameter lowers the clock frequency to 100 Hz?
That's weird, it should be 250 HZ. Hmm, resetting it, needs kernel recompiling, are you sure you use a Beta4 kernel and cat /proc/sys/kernel/HZ shows 250? However, the reason why C3 isn't used very often, is probably that bus master activity (DMA transfers) prevent the processor to go into C3. Try to not load any USB/PCMCIA/Firewire/... modules. Also some graphics card options could produce heavy DMA transfers. Also set the ClockMode (or similar) Radeon option in Xorg.conf as described before. This should help a lot.
Theoretically it could also be throttling, but I doubt it: cat /proc/acpi/processor/*/throttling or powersave -T You could increase allowed throttling, if the machine is idle using the powersave daemon. Default is 50% throttling after 10 seconds idle time (also for performance scheme?)I have already tried setting the maximum throttling allowed to 87%. Since in my experiment the system is always in scheme_powersave, it is not relevant to change this setting in scheme_performance.
Forget throttling, it won't help much.
Thomas
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