Applied this series to acpi-test in anticipation that Venki is about to send some incremental patches to address the feedback on it. thanks, -Len On Saturday 24 March 2007 03:46, Adam Belay wrote: > Hi All, > > Here is my first take at implementing an idle PM governor that takes > full advantage of NO_HZ. I call it the 'menu' governor because it > considers the full list of idle states before each entry. > > I've kept the implementation fairly simple. It attempts to guess the > next residency time and then chooses a state that would meet at least > the break-even point between power savings and entry cost. To this end, > it selects the deepest idle state that satisfies the following > constraints: > 1. If the idle time elapsed since bus master activity was detected > is below a threshold (currently 20 ms), then limit the selection > to C2-type or above. > 2. Do not choose a state with a break-even residency that exceeds > the expected time remaining until the next timer interrupt. > 3. Do not choose a state with a break-even residency that exceeds > the elapsed time between the last pair of break events, > excluding timer interrupts. > > This governor has an advantage over "ladder" governor because it > proactively checks how much time remains until the next timer interrupt > using the tick infrastructure. Also, it handles device interrupt > activity more intelligently by not including timer interrupts in break > event calculations. Finally, it doesn't make policy decisions using the > number of state entries, which can have variable residency times (NO_HZ > makes these potentially very large), and instead only considers sleep > time deltas. > > The menu governor can be selected during runtime using the cpuidle sysfs > interface like so: > "echo "menu" > /sys/devices/system/cpu/cpuidle/current_governor" > > This patchset applies against 2.6.21-rc4 plus the latest from the acpi > testing tree, which is available here: > ftp://ftp.kernel.org/pub/linux/kernel/people/lenb/acpi/patches/test/2.6.21/acpi-test-20070126-2.6.21-rc4.diff.bz2 > > I'd really appreciate any comments, benchmarks, or suggestions. > > Cheers, > Adam > > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
