Re: [PATCH 0/4 v4] ext3/4: enhance fsync performance when using CFQ

From: KOSAKI Motohiro
Date: Tue May 18 2010 - 22:05:30 EST

Hi Jeff,

> This patch series addresses a performance problem experienced when running
> io_zone with small file sizes (from 4KB up to 8MB) and including fsync in
> the timings. A good example of this would be the following command line:
> iozone -s 64 -e -f /mnt/test/iozone.0 -i 0
> As the file sizes get larger, the performance improves. By the time the
> file size is 16MB, there is no difference in performance between runs
> using CFQ and runs using deadline. The storage in my testing was a NetApp
> array connected via a single fibre channel link. When testing against a
> single SATA disk, the performance difference is not apparent.


Can this patch help to reduce a pain of following much small files issue?

Now, userland folks think sync() is faster than fsync() on ext4. I don't
hope spread this unrecommended habit widely.

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