Messages in this thread |  | | Date | Thu, 18 Jan 2001 17:23:44 -0800 | From | Mike Kravetz <> | Subject | Re: multi-queue scheduler update |
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On Fri, Jan 19, 2001 at 02:08:52AM +0100, Andi Kleen wrote: > On Thu, Jan 18, 2001 at 08:00:16PM -0500, Mark Hahn wrote: > > > > microseconds/yield > > > > # threads 2.2.16-22 2.4 2.4-multi-queue > > > > ------------ --------- -------- --------------- > > > > 16 18.740 4.603 1.455 > > > > > > I remeber the O(1) scheduler from Davide Libenzi was beating the mainline O(N) > > > > isn't the normal case (as in "The Right Case to optimize") > > where there are close to zero runnable tasks? what realistic/sane > > scenarios have very large numbers of spinning threads? all server > > situations I can think of do not. not volanomark -loopback, surely! > > I think the main point of Mike's patch is decreasing locking and cache line > bouncing overhead of multi cpu scheduling, not optimizing lots of runnable tasks. > > > -Andi
Andi is correct. Although the results I posted may seem to indicate we are concentrating on high thread counts, this is really secondary to reducing lock contention within the scheduler. A co-worker down the hall just ran pgbench (a postgresql db) benchmark and saw contention on the runqueue lock at 57%. Now, I know nothing about this benchmark, but it will be interesting to see what happens after applying my patch.
-- Mike Kravetz mkravetz@sequent.com IBM Linux Technology Center - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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