Messages in this thread | | | Date | Mon, 25 Mar 2002 17:57:45 -0800 | From | Mike Fedyk <> | Subject | Re: Putrid Elevator Behavior 2.4.18/19 |
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On Mon, Mar 25, 2002 at 05:45:55PM -0800, David Rees wrote: > On Mon, Mar 25, 2002 at 06:16:45PM -0700, Jeff V. Merkey wrote: > > > > The elevator starvation change went into 2.4.19-pre1 I think. > > > > It shouldn't affect the problem which you've described - that > > > > change improved the situation where tasks were sleeping for > > > > long periods when they want to insert new requests. But the > > > > problem which you're observing appears to affect already-inserted > > > > requests. > > > > > > > > "Several minutes" is downright odd. From your description > > > > it seems that all the requests are writes, but some of the > > > > writes (at a remote end of the disk) are being bypassed far > > > > too many times. > > > > > > > > The bypass count _is_ tunable. Although it sounds like the logic > > > > has come unstuck in some manner, it would be interesting if > > > > changing the elevator latency parameters for that queue affected > > > > the situation. > > > > > > > > Have you experimented with `elvtune -r NNN /dev/foo' and > > > > `elvtune -w NNN /dev/foo'? > > > > > > No, but I will test this tonight. I am in tonight working on > > > this problem until I run it down. > > > > I have been running a test run against 2.4.19-pre4 (and later) for > > over a week non-stop and the elevator problem appears to have been > > corrected by this fix. I will update further if the problem > > resurfaces. > > Jeff, > > Did upgrading to 2.4.19-pre4 by itself fix your problems, or did you need to > tweak with elvtune as well? If so, what values did you find produced > optimal results? >
I'd doubt that Jeff's optimal (magic) elvtune numbers would be much use to other people, as elvtune should be set for each particular workload.
Now, if we had a small guide that said "these value ranges/combinations have worked best for $this workload" that would be quite helpful... - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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