Messages in this thread | | | Subject | Re: [ckrm-tech] Re: [PATCH 0/9] CPU controller | From | Mike Galbraith <> | Date | Fri, 28 Apr 2006 12:42:51 +0200 |
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On Fri, 2006-04-28 at 20:26 +1000, Con Kolivas wrote: > On Friday 28 April 2006 20:16, Mike Galbraith wrote: > > > How many tasks? Your function was O(n) so the more tasks the longer that > > > max value was. > > > > Nope. It's not O(tasks), it's O(occupied_queues). Occupied queues is > > generally not a large number. > > Ok well that P4 does about 700,000 context switches per second so 4us sounds > large to me.
I'm not always calling it now, only when necessary. In any case, I'd much rather pay 4us (it averages 1) every 100ms when at 100% cpu than take a multi-second latency hit for high priority tasks as now occurs with a heavy load when the array switch is forced. This hit is more likely with my (unfortunately necessary) change to wake tasks on the expired array. That's why I started trying to eliminate the switch.
-Mike
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