Messages in this thread | | | From | Con Kolivas <> | Subject | Re: [ckrm-tech] Re: [PATCH 0/9] CPU controller | Date | Fri, 28 Apr 2006 20:26:38 +1000 |
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On Friday 28 April 2006 20:16, Mike Galbraith wrote: > On Fri, 2006-04-28 at 20:09 +1000, Con Kolivas wrote: > > On Friday 28 April 2006 17:46, Mike Galbraith wrote: > > > On Fri, 2006-04-28 at 09:11 +0200, Mike Galbraith wrote: > > > > On Fri, 2006-04-28 at 09:56 +0400, Kirill Korotaev wrote: > > > > > I'm also pretty sure, that CPU controller based on timeslice tricks > > > > > behaves poorly on burstable load patterns as well and with > > > > > interactive tasks. So before commiting I propose to perform a good > > > > > testing on different load patterns. > > > > > > > > Yes, it can only react very slowly. > > > > > > Actually, this might not be that much of a problem. I know I can > > > traverse queue heads periodically very cheaply. Traversing both active > > > and expired arrays to requeue starving tasks once every 100ms costs max > > > 4usecs (3GHz P4) for a typical distribution. > > > > 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.
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