Messages in this thread | | | Date | Sun, 05 Oct 2003 13:13:10 +1000 | From | Nick Piggin <> | Subject | Re: 2.6.0-test6 scheduler goodness |
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David B Harris wrote:
>Hey guys. Using Linux 2.6.0-test6, and have a few scheduler comments >(first though, good work! :) see below): > >1) I'm a fairly heavy user/developer. 2.4.x's stock scheduler has always >been excellent for me. Just in case I was missing out, I tried preempt >patches, lowlatency patches, different VMs/schedulers and such. All of >them reduced throughput and responsiveness noticeably. > >2) I've been tracking 2.5.x/2.6.0-test* for a while, and up to and >including 2.6.0-test4, I had the same problems as I did with non-stock >2.4.x schedulers; in other words, both throughput and responsiveness >were worse than I needed (in other words, they weren't as good as what I >was used to). > >3) I'm aware of how easy it is to create a world-class workstation >scheduler, and how hard it is to make a scheduler that's excellent in >all workload cases ;) > >4) In either 2.6.0-test5, or 2.6.0-test6 (I'm using 2.6.0-test6, I >skipped test5), responsiveness was magically fixed for my workload case. >I still have lower throughput, apparently (big compiles and whatnot take >about 20% longer), but I recently got a CPU upgrade so I don't >particularily notice it - the CPU upgrade was a pretty major one. > >Allright, so, in that context, here are some excerpts form a >conversation I had on IRC: > >[14:42:14] <ElectricElf> Heh, impressive: >[14:42:14] <ElectricElf> 14:41:55 up 14:58, 6 users, load average: 171.82, 319.28, 475.21 >[14:44:51] <ElectricElf> Oh, heh, that explains why: >[14:44:59] <ElectricElf> [ david@willow: ~/ ]$ ps auwwx | wc -l >[14:44:59] <ElectricElf> 3381 >[14:45:22] <steve> mothers of christ >[14:45:31] <ElectricElf> They're all procmail instances. >[14:45:34] <ElectricElf> formail/procmail sucks. >[14:45:40] <ElectricElf> Highest loadavg I've ever seen though. >[14:45:47] <steve> same. >[14:46:40] <ElectricElf> In 2.6.x's defence, though, I didn't even notice it > was that bad. >[14:46:51] <ElectricElf> Still web browsing fairly normally. >[14:47:04] <ElectricElf> Disk was thrashing, but I just assumed it was > slugging through all the mails sequentially. >[14:47:50] <ElectricElf> I think I have about 3200 procmail processes polling > for a lockfile every second. >[14:48:02] <ElectricElf> ... and one of 'em died, not releasing lockfile :) >[14:48:33] <steve> hahaha >[14:48:46] <ElectricElf> [ david@willow: ~/ ]$ ps auwwx | wc -l >[14:48:46] <ElectricElf> 3379 >[14:48:51] <ElectricElf> Yah. They're all just kind of sitting there. >[14:48:59] * ElectricElf removes the lock and waits for the shitstorm >[14:49:15] <ElectricElf> Heh. Didn't do much at all. >[14:49:18] <ElectricElf> *sigh* >[14:49:24] * ElectricElf killalls procmail ># Annotation: ># I had suspended the formail process which had all the procmails traced. ># ># A few processes were very, very unhappy at this point: notably, my Screens ># and X were unable to process keyboard/mouse input. There was quite the ># swapstorm as procmail processes which had been swapped out were brought back ># in and killed. However, it passed in about 30 seconds, and I was able to ># watch the progress as my pretty much everything appeared to at least be able ># to continue with output; gkrellm and X didn't appear to be struggling in ># that manner. >
Hi David, You said your box was swapping heavily - this is probably the cause of your problems. Can you reproduce bad behaviour when the box is not swapping?
Try my scheduler patches if you like. http://www.kerneltrap.org/~npiggin/v15a/
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