On Fri, Apr 1, 2016 at 8:31 PM, Doug Smythies <dsmyth...@telus.net> wrote: > On 2106.034.01 10:45 Srinivas Pandruvada wrote: >> On Fri, 2016-04-01 at 16:06 +0200, Jörg Otte wrote: >> > > > > > >>> Done. Attached the tracer. >>> For me it looks like the previous one of the failing case. >> >> The traces show that idle task is constantly running without sleep. > > No, they (at least the first one, I didn't look at the next one yet) > show that CPUs 2 and 3 are spending around 99% of their time not in state > C0.
How do you figure that out if I may ask? It is not so obvious to me to be honest. > That the sample rate is ending up at ~10 Milliseconds, indicates some > high frequency (>= 100Hz) events on those CPUs. Those events, apparently, > take very little CPU time to complete, hence a load of about 1% on average. > > By the way, I can recreate the high sample rate with virtually no load > on my system easy, but so far have been unable to get the high CPU > frequencies observed by Jörg. I can get my system to about a target pstate of > 20 where it should have remained at 16, but that is about it. > >> The driver is processing samples for idle task for every 10ms and >> aperf/mperf are showing that we are always in turbo mode for idle task. > > That column pretty much always says "idle" (or swapper for my way of doing > things). I have not found it to very useful as an indicator, and considerably > more so since the utilization changes. > >> >> Need to find out why idle task is not sleeping. > > I contend that is it. Why? Thanks, Rafael
