David Vengerov wrote: > Mark, > Thank you, Mark, for the link describing the Intel Enhanced Intel > SpeedStep Technology. I noticed that they suggest for the kernel to poll > each CPU at regular time intervals, asking about its utilization. Then, > they plan to adjust the CPU frequency based on its utilization. > > Do you guys think that the CPU frequency should be changed in response > to changes in CPU utilization?
Sure - if the CPU is 100% busy and then becomes idle, reducing CPU frequency seems like a reasonable plan. Of course, if the only thing the user cares about is response latency to infrequent events, this policy won't work well. But as a default, it's a pretty good choice. > If so, should we expect the CPU > utilization to rise as the CPU frequency is decreased and vice versa? Depends on workload. If code is memory bound on a non-threaded CPU when it runs, CPU freq. will have little effect on either throughput or CPU utilization. On the other hand, if we're computing Pi periodically, I would expect utilization to go up as freq. goes down. - Bart -- Bart Smaalders Solaris Kernel Performance barts at cyber.eng.sun.com http://blogs.sun.com/barts
