Re: Linux memory zone reclaim

On Tue, Jul 17, 2012 at 7:52 PM, Greg Smith <greg(at)2ndquadrant(dot)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.