Description of problem: cpuspeed inreases cpu frequency when there is a lot of disk i/o. I.e. when a lot of time is spent in 'waiting'. This causes a lot of wasted power since disk i/o won't increase just because the cpu is faster (since that's rarely the bottle neck). Version-Release number of selected component (if applicable): 2.4-13.1.39 How reproducible: Every time.
are your disks in DMA mode ?
Yes they are. Running 'dd if=/dev/hda of=/dev/null' puts the cpu in full speed and top reports: Cpu(s): 3.3% us, 9.3% sy, 0.0% ni, 0.0% id, 85.4% wa, 2.0% hi, 0.0% si
Created attachment 111898 [details] Patch to measure iowait This patch gives the desired behaviour.
Modern cpuspeed has this behaviour. Marking as resolved.