On Feb 10, 2010, at 1:37 AM, Greg Smith wrote:
Jeff wrote:
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
pgiosim doesn't really mix writes into there though, does it? The
mixed read/write situations are the ones where the scheduler stuff
gets messy.
It has the abillity to rewrite blocks randomly as well - but I
honestly don't remember if I did that during my cfq/deadline test.
I'd wager I didn't. Maybe I'll get some time to run some more tests
on it in the next couple days
--
Greg Smith 2ndQuadrant Baltimore, MD
PostgreSQL Training, Services and Support
greg@xxxxxxxxxxxxxxx www.2ndQuadrant.com
--
Jeff Trout <jeff@xxxxxxxxxxxxx>
http://www.stuarthamm.net/
http://www.dellsmartexitin.com/
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