Messages in this thread | | | Date | Tue, 12 Feb 2002 17:55:18 +0100 | From | Jens Axboe <> | Subject | Re: Linux 2.4.18-pre9-ac1 |
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On Tue, Feb 12 2002, Alan Cox wrote: > > > > I want to find out why it was done first and then test it. Leaving it out > > > > will ensure it bugs me until I test it > > > > > > If you leave it out, you surely want to make sure that the other request > > > init and re-init paths agree on the clustering for MO devices. Because > > > they don't. > > No - I want to run a test set with an M/O drive before and after the change > and see what it shows in real life. I suspect nothing much.
That completely ignores that there is a _bug_ there currently. There was a reason I removed disabled clustering, you know... 2.4 before the change oopses, 2.4.18-preX (forget when Marcelo took the patch) has it fixed.
> > Now, disabling request merging for MO devices might make a whole lot > > more sense. That might be worth while trying, and I'd be happy to give > > you a patch to try that out instead. > > I don't think that should be required actually. The killer on M/O disks > is seek time, and to an extent rotational latency (its 3 trips round a > cheaper M/O disk to rewrite a sector). If anything clustering writes to > the same track should be a big win.
You are probably right. Can't make pigs fly :-)
-- Jens Axboe
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