Re: Linux memory zone reclaim - Mailing list pgsql-performance

From Dave Crooke
Subject Re: Linux memory zone reclaim
Date
Msg-id CALi4UpjNs6d5w1XFkprmQuvmK+H9ucs9ua9A+TW_RWfJvnw0RA@mail.gmail.com
Whole thread Raw
In response to Re: Linux memory zone reclaim  (Scott Marlowe <scott.marlowe@gmail.com>)
List pgsql-performance

On the larger, cellular Itanium systems with multiple motherboards (rx6600 to Superdome) Oracle has done a lot of tuning with the HP-UX kernel calls to optimize for NUMA issues. Will be interesting to see what they bring to Linux.

On Jul 17, 2012 9:01 PM, "Scott Marlowe" <scott.marlowe@gmail.com> wrote:
On Tue, Jul 17, 2012 at 7:52 PM, Greg Smith <greg@2ndquadrant.com> wrote:
> Newer Linux systems with lots of cores have a problem I've been running into
> a lot more lately I wanted to share initial notes on.  My "newer" means
> running the 2.6.32 kernel or later, since I mostly track "enterprise" Linux
> distributions like RHEL6 and Debian Squeeze.  The issue is around Linux's
> zone_reclaim feature.  When it pops up, turning that feature off help a lot.
> Details on what I understand of the problem are below, and as always things
> may have changed already in even newer kernels.

SNIP

> Scott Marlowe has been griping about this on the mailing lists here for a
> while now, and it's increasingly trouble for systems I've been seeing lately
> too.  This is a well known problem with MySQL:
> http://blog.jcole.us/2010/09/28/mysql-swap-insanity-and-the-numa-architecture/

Thanks for the link, I'll read up on it.  I do have access to large
(24 to 40 core) NUMA machines so I might try some benchmarking on them
to see how they work.

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