|Summary:||cpuspeed doesn't handle hyperthreaded cpu's effectively|
|Product:||Red Hat Enterprise Linux 4||Reporter:||Eric Jones <enjones>|
|Component:||kernel-utils||Assignee:||Jarod Wilson <jarod>|
|Status:||CLOSED INSUFFICIENT_DATA||QA Contact:||Brian Brock <bbrock>|
|Fixed In Version:||Doc Type:||Bug Fix|
|Doc Text:||Story Points:||---|
|Last Closed:||2007-06-04 21:37:19 UTC||Type:||---|
|oVirt Team:||---||RHEL 7.3 requirements from Atomic Host:|
Description Eric Jones 2005-07-15 20:17:53 UTC
From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.8) Gecko/20050512 Red Hat/1.0.4-1.4.1 Firefox/1.0.4 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): kernel-utils-2.4-13.1.48 How reproducible: Always 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. Additional info:
Comment 1 Jarod Wilson 2007-01-24 14:53:32 UTC
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 through them...
Comment 2 Jarod Wilson 2007-06-04 21:37:19 UTC
4+ months of no activity, 1.5+ years since hearing from the original poster, closing out bug.