| From: | Jeff <threshar(at)torgo(dot)978(dot)org> |
|---|---|
| To: | david(at)lang(dot)hm |
| Cc: | Greg Smith <greg(at)2ndquadrant(dot)com>, Hannu Krosing <hannu(at)2ndquadrant(dot)com>, Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>, pgsql-performance(at)postgresql(dot)org, Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at> |
| Subject: | Re: Linux I/O tuning: CFQ vs. deadline |
| Date: | 2010-02-09 19:14:11 |
| Message-ID: | 39DDB34B-C375-46ED-83D2-688A32188100@torgo.978.org |
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| Lists: | pgsql-performance |
On Feb 8, 2010, at 11:35 PM, david(at)lang(dot)hm wrote:
>
>> And, yes, the whole I/O scheduling approach in Linux was just
>> completely redesigned for a very recent kernel update. So even
>> what we think we know is already obsolete in some respects.
>>
I'd done some testing a while ago on the schedulers and at the time
deadline or noop smashed cfq. Now, it is 100% possible since then
that they've made vast improvements to cfq and or the VM to get better
or similar performance. I recall a vintage of 2.6 where they severely
messed up the VM. Glad I didn't upgrade to that one :)
Here's the old post: http://archives.postgresql.org/pgsql-performance/2008-04/msg00155.php
--
Jeff Trout <jeff(at)jefftrout(dot)com>
http://www.stuarthamm.net/
http://www.dellsmartexitin.com/
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