Messages in this thread | | | Date | Wed, 11 Aug 2004 13:46:05 +1000 | From | Peter Williams <> | Subject | Re: Scheduler fairness problem on 2.6 series (Attn: Nick Piggin and others) |
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Con Kolivas wrote: > Peter Williams writes: > >> Peter Williams wrote: >> >>> Peter Williams wrote: >>> >>>> William Lee Irwin III wrote: >>>> >>>>> On Tue, Aug 10, 2004 at 07:21:43PM -0700, spaminos-ker@yahoo.com >>>>> wrote: >>>>> >>>>>> I am not very familiar with all the parameters, so I just kept the >>>>>> defaults >>>>>> Anything else I could try? >>>>>> Nicolas >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> No. It appeared that the SPA bits had sufficient fairness in them to >>>>> pass this test but apparently not quite enough. >>>>> >>>> >>>> The interactive bonus may interfere with fairness (the throughput >>>> bonus should actually help it for tasks with equal nice) so you >>>> could try setting max_ia_bonus to zero (and possibly increasing >>>> max_tpt_bonus). With "eb" mode this should still give good >>>> interactive response but expect interactive response to suffer a >>>> little in "pb" mode however renicing the X server to a negative >>>> value should help. >>> >>> >>> >>> I should also have mentioned that fiddling with the promotion >>> interval may help. >> >> >> Having reread your original e-mail I think that this problem is >> probably being caused by the interactive bonus mechanism classifying >> the httpd server threads as "interactive" threads and giving them a >> bonus. But for some reason the daemon is not identified as >> "interactive" meaning that it gets given a lower priority. In this >> situation if there's a large number of httpd threads (even with >> promotion) it could take quite a while for the daemon to get a look >> in. Without promotion total starvation is even a possibility. >> >> Peter >> PS For both "eb" and "pb" modes, max_io_bonus should be set to zero on >> servers (where interactive responsiveness isn't an issue). >> PPS For "sc" mode, try setting "interactive" to zero and "compute" to 1. > > > No, compute should not be set to 1 for a server. It is reserved only for > computational nodes, not regular servers. "Compute" will increase > latency which is undersirable.
Sorry, my misunderstanding.
Peter -- Peter Williams pwil3058@bigpond.net.au
"Learning, n. The kind of ignorance distinguishing the studious." -- Ambrose Bierce
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