Red Hat Bugzilla – Bug 474132
ondemand on scaling erratic and inconsistent on T8100
Last modified: 2009-06-30 15:26:45 EDT
Description of problem:
On my T8100 notebook, the ondemand governor will only take the processor to full-speed (2.1 GHz) if a demanding job is running on Core 1. If the job is on Core 0, it'll only go up to 1.2 GHz. scaling_max_freq is correct at 2101000 in sysfs for both CPUs.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Get a job running on Core 0.
CPU only goes up to 1.2 GHz.
CPU goes up to maximum speed (2.1 GHz).
For ACPI dump see bug 448150.
I've just checked and this bug does not appear to manifest in kernel-126.96.36.199-53.fc9.x86_64.
Still present in kernel-188.8.131.52-144.fc10.x86_64. It now caps on 1.6 GHz or sometimes 2.100 GHz (maximum is actually 2.101 GHz). Either way, load metering differs between Core 0 and Core 1.
kernel-184.108.40.206-155.fc10.x86_64 is as comment #2.
I've furthermore observed that, when *first booted on battery power*, the CPU will [eventually] scale up to 2.1 GHz. Normally on battery power, it should only go to 1.2 GHz. If I press the "low power" button, it *does* start to limit itself to 1.2 GHz as it should, and also thereafter when on battery power; on mains, all speeds are available (provided the governor selects them).
ondemand scaling seems much improved in kernel-2.6.29-0.20.rc3.git12.fc10.x86_64, now supporting independent core frequencies and correct metering. Closing in deference to upstream.
Re-opening, it's not fixed. Core 0 actually appears to operate slower than reported in sysfs.