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

Bill Davidsen
2007-08-07T19:08:52Z

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@tmr.com>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot