Messages in this thread |  | | Date | Tue, 3 Sep 2002 12:28:18 +0200 (CEST) | From | Ingo Molnar <> | Subject | Re: Problem with the O(1) scheduler in 2.4.19 |
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On Tue, 3 Sep 2002, Tobias Ringstrom wrote:
> For the case of a game server, this means that when the CPU utilization > gets above 50% (roughly), it will switch from -5 to +5 in dynamic > priority in a few seconds and stay there until the CPU utilization drops > under 50%. > > Is my analysis correct, and is this what we want?
do you expect a task that uses up 50% CPU time over an extended period of time to be rated 'interactive'?
we might make the '50%' rule to be '100% / nr_running_avg', so that if your task is the only one in the system then it gets rated interactive - but i suspect it will still be rated a CPU hog if it keeps trying to use up 50% of CPU time even during busier periods. I have tried the (1/nr_running) rule in earlier incarnations of the scheduler, and it didnt make much difference, but we obviously need a boundary case like yours to see the differences.
> I tried that yesterday (without the O(1) scheduler), and it does wonders > for the in-game latency (i.e. ping). I suppose that the dynamic prio > will still be +5 at 70% CPU utilization even with a HZ of 1000 using the > O(1) scheduler. Why would it make a difference?
(it could in theory make a difference in some rare cases, in which the frequency of sampling resonates with internal timings of the application - i asked for this only to make sure there are no interactions.)
Ingo
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