Messages in this thread | | | Date | Thu, 26 Mar 2009 15:39:53 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: ext3 IO latency measurements (was: Linux 2.6.29) |
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On Thu, 26 Mar 2009, Jan Kara wrote: > > Reads are measurably better with the patch - the test with cat you > describe below took ~0.5s per file without the patch and always less than > 0.02s with the patch. So it seems to help something.
That would seem to be a _huge_ improvement.
Reads are the biggest issue for starting a new process (eg starting firefox while under load), and if cat'ing that small file improved by that much, then I bet there's a huge practical implication for a lot of desktop uses.
The fundamental fsync() latency problem we sadly can't help much with, the way ext3 seems to work. But I do suspect that the whole "don't synchronize with the journal for normal write-outs" may end up helping even fsync just a bit, if only because I suspect it will improve writeout throughput too and thus avoid one particular bottleneck.
Linus
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