Messages in this thread |  | | | Date | Fri, 29 Oct 2004 17:31:48 +1000 | | From | Nathan Scott <> | | Subject | Re: Filesystem performance on 2.4.28-pre3 on hardware RAID5. |
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Hi there,
On Fri, Oct 29, 2004 at 12:43:30AM +0200, Martin MOKREJ? wrote: > "mount -t xfs -o async" unexpectedly kills random seek performance, > but is still a bit better than with "-o sync". ;) Maybe it has to do > with the dramatic jump in CPU consumption of this operation, > as it in both cases it takes about 21-26% instead of usual 3%. > Why? Isn't actually async default mode?
Thats odd. Actually, I'm not sure what the "async" option is meant to do, it isn't seen by the fs afaict (XFS isn't looking for it)... we also use the generic_file_llseek code in XFS ... so we're not doing anything special there either -- some profiling data showing where that CPU time is spent would be insightful.
> Sequential create /Create > Random create /Create > XFS 60-120 ms
You may get better results using a version 2 log (mkfs option) with large in-core log buffers (mount option) for these (which mkfs version are you using atm?)
cheers.
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