Vinay Devadas wrote: >> when IDA is enabled, if DTrace says we are in P0, >> we really in P0 in terms of OSPM. So not necessary to change p-state >> index and percent. >> > > Even when IDA is enabled and Dtrace says we are in P0, the > ratio APERF/MPERF *may be* <=1. This means we were just > running at max non turbo frequency (marketed as P1) and not > actually in turbo mode (marketed as P0). Therefore it is > necessary to change p-state index and percent and do check. Correct > me if I am wrong. > P0 is not equal to turbo mode. P0 means the system is requesting to the speed of the max performance. When Turbo mode is enabled, P0 give the system a chance to go into turbo mode, but whether the processor enter turbo mode or not is determined by the hardware. So, even if APERF/MPERF may be < 1, if DTrace says we are in P0, we should let PowerTOP and users know the system is requesting max performance speed, not max non turbo speed.
Thanks, -Aubrey
