Red Hat Bugzilla – Bug 163397
cpuspeed doesn't handle hyperthreaded cpu's effectively
Last modified: 2007-11-30 17:07:19 EST
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Description of problem:
When using a HyperThreaded Pentium 4 CPU, the cpuspeed daemon doens't use an effective algorithm for determining the current CPU utilizization. Since a single CPU intensive process only runs on one "virtual" CPU, the other CPU appears 100% idle, giving a net system usage of 50%. cpuspeed sees this and lowers the clock speed, slowing down the otherwise CPU intensive application. When running on a hyperthreaded system, cpuspeed should use the most active "virtual" processor as its gauge for current system activity.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. start cpuspeed
2. run an intense cpu benchmark on one "virtual" processor
3. cat /proc/cpuinfo and watch the processor get slowed to its lowest state (2.8 GHz on my 3.6 GHz box)
Actual Results: The cpu was frequency scaled down to its lowest state.
Expected Results: The cpu should have run at the maximum clock speed since the benchmark was utilizing 100% of one of the "virtual" processors.
Is this still an issue with the latest RHEL4 kernel and kernel-utils packages?
I'm taking over all cpu frequency scaling bugs, and trying to work my way
4+ months of no activity, 1.5+ years since hearing from the original poster,
closing out bug.