Messages in this thread | | | From | Leroy van Logchem <> | Subject | Re: huge improvement with per-device dirty throttling | Date | Tue, 04 Sep 2007 11:37:36 +0200 |
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Andrea Arcangeli wrote: > On Wed, Aug 22, 2007 at 01:05:13PM +0200, Andi Kleen wrote: >> Ok perhaps the new adaptive dirty limits helps your single disk >> a lot too. But your improvements seem to be more "collateral damage" @) >> >> But if that was true it might be enough to just change the dirty limits >> to get the same effect on your system. You might want to play with >> /proc/sys/vm/dirty_* > > The adaptive dirty limit is per task so it can't be reproduced with > global sysctl. It made quite some difference when I researched into it > in function of time. This isn't in function of time but it certainly > makes a lot of difference too, actually it's the most important part > of the patchset for most people, the rest is for the corner cases that > aren't handled right currently (writing to a slow device with > writeback cache has always been hanging the whole thing).
Self-tuning > static sysctl's. The last years we needed to use very small values for dirty_ratio and dirty_background_ratio to soften the latency problems we have during sustained writes. Imo these patches really help in many cases, please commit to mainline.
-- Leroy
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