Re: Major Linux performance regression; shouldn't we be worried about RHEL6?

Josh Berkus wrote:
> Domas (of Facebook/Wikipedia, MySQL geek) pointed me to this report:
>
> http://www.phoronix.com/scan.php?page=article&item=linux_perf_regressions&num=1
> http://www.phoronix.com/scan.php?page=article&item=ext4_then_now&num=6
>
The main change here was discussed back in January:

http://archives.postgresql.org/message-id/4B512D0D.4030909@2ndquadrant.com

What I've been doing about this is the writing leading up to
http://wiki.postgresql.org/wiki/Reliable_Writes so that when RHEL6 does
ship, we have a place to point people toward that makes it better
documented that the main difference here is a reliability improvement
rather than a performance regression.  I'm not sure what else we can do
here, other than organizing more testing for kernel bugs in this area on
RHEL6.  The only way to regain the majority of the "lost" performance
here is to turn off synchronous_commit in the default config.

--
Greg Smith   2ndQuadrant US    greg@2ndQuadrant.com   Baltimore, MD
PostgreSQL Training, Services and Support        www.2ndQuadrant.us
"PostgreSQL 9.0 High Performance": http://www.2ndQuadrant.com/books