Re: Linux I/O tuning: CFQ vs. deadline

From: Jeff
Subject: Re: Linux I/O tuning: CFQ vs. deadline
Date: ,
Msg-id: 39DDB34B-C375-46ED-83D2-688A32188100@torgo.978.org
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In response to: Re: Linux I/O tuning: CFQ vs. deadline  ()
Responses: Re: Linux I/O tuning: CFQ vs. deadline  (Greg Smith)
List: pgsql-performance

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Linux I/O tuning: CFQ vs. deadline  (Greg Smith, )
 Re: Linux I/O tuning: CFQ vs. deadline  ("Albe Laurenz", )
  Re: Linux I/O tuning: CFQ vs. deadline  ("Kevin Grittner", )
   Re: Linux I/O tuning: CFQ vs. deadline  (Greg Smith, )
    Re: Linux I/O tuning: CFQ vs. deadline  (Josh Berkus, )
     Re: Linux I/O tuning: CFQ vs. deadline  (Scott Marlowe, )
     Re: Linux I/O tuning: CFQ vs. deadline  (Mark Wong, )
     Re: Linux I/O tuning: CFQ vs. deadline  (Scott Carey, )
     Re: Linux I/O tuning: CFQ vs. deadline  (Greg Smith, )
     Re: Linux I/O tuning: CFQ vs. deadline  (Jeff Davis, )
 Re: Linux I/O tuning: CFQ vs. deadline  (Greg Smith, )
  Re: Linux I/O tuning: CFQ vs. deadline  (, )
   Re: Linux I/O tuning: CFQ vs. deadline  (Jeff, )
    Re: Linux I/O tuning: CFQ vs. deadline  (Greg Smith, )
     Re: Linux I/O tuning: CFQ vs. deadline  (Scott Marlowe, )
      Re: Linux I/O tuning: CFQ vs. deadline  (Greg Smith, )
       Re: Linux I/O tuning: CFQ vs. deadline  (, )
        Re: Linux I/O tuning: CFQ vs. deadline  (Greg Smith, )
     Re: Linux I/O tuning: CFQ vs. deadline  (Jeff, )
     Re: Linux I/O tuning: CFQ vs. deadline  (Scott Carey, )

On Feb 8, 2010, at 11:35 PM,  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 <>
http://www.stuarthamm.net/
http://www.dellsmartexitin.com/





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