Messages in this thread | | | Date | Thu, 31 Jul 2003 10:12:51 -0400 (EDT) | Subject | Re: linux-2.6.0-test2: Never using pm_idle (CPU wasting power) | From | "Charles Lepple" <> |
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Christian Vogel said: > on a Thinkpad 600X I noticed the CPU getting very hot. It turned > out that pm_idle was never called (which invokes the ACPI pm_idle > call in this case) and default_idle was used instead.
The amd76x_pm patch[1] also hooks pm_idle, and while I'm not 100% sure about this (haven't instrumented it all the way), it also appears that pm_idle is not being called (for up to an hour, in some cases). Sometimes it takes only a few minutes, and other times, it appears to kick in after heavy CPU usage (kernel compiles, cpuburn, etc.). After pm_idle is called once, things seem normal-- after the system quiesces, pm_idle is always called when nothing is ready to run.
Since the amd76x_pm patch appears to work pretty well under 2.4.x, I get the feeling that the problem lies in the cpu_idle() function. (But I realize there could be SMP interactions in this case-- in the amd76x_pm patch, C2 isn't entered unless both CPUs are idle; hence the need for further instrumentation.)
[1] http://marc.theaimsgroup.com/?l=linux-kernel&m=105665646000758&w=3
-- Charles Lepple <clepple@ghz.cc> http://www.ghz.cc/charles/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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