Re: [PATCH 00/23] per device dirty throttling -v8

[Bill Davidsen]

Alan Cox wrote:
> > i cannot over-emphasise how much of a deal it is in practice. Atime 
> > updates are by far the biggest IO performance deficiency that Linux has 
> > today. Getting rid of atime updates would give us more everyday Linux 
> > performance than all the pagecache speedups of the past 10 years, 
> > _combined_.
> >
> > it's also perhaps the most stupid Unix design idea of all times. Unix is 
> > really nice and well done, but think about this a bit:
>
> Think about the user for a moment instead. 
>
> Do things right. The job of the kernel is not to "correct" for
> distribution policy decisions. The distributions need to change policy.
> You do that by showing the distributions the numbers. 
>
> With a Red Hat on if we can move from /dev/hda to /dev/sda in FC7 then we
> can move from atime to noatime by default on FC8 with appropriate release
> note warnings and having a couple of betas to find out what other than
> mutt goes boom.

Is there really enough benefit between relatime and noatime to justify 
that? If atime doesn't get updated at all it *will* impact operations, 
and unless there's a real performance gain the path which provides at 
least nominal POSIX compliance seems best.

Plauger's law of least astonishment.

--
Bill Davidsen <davidsen@xxxxxxx>
  "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot
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