Messages in this thread | | | Date | Wed, 20 Mar 2002 23:45:52 -0700 | From | "Jeff V. Merkey" <> | Subject | Re: Putrid Elevator Behavior 2.4.18/19 |
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On Wed, Mar 20, 2002 at 05:22:18PM -0800, Andrew Morton wrote: > "Jeff V. Merkey" wrote: > > > > ... > > > I will comply. I tested with pre-3 patches and still saw this problem?? > > > Let me go and check the patches I applied to verify, I may not have > > > applied the correct patch. > > > > > > Jeff > > > > I verified we were using a stock 2.4.18 kernel on the specific system > > without the pre-3 patches installed. We have been testing with the > > latest patches but not on this system. We will apply and retest and > > I will verify. > > > > 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.
Jeff
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