Re: high io BUT huge amount of free memory - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: high io BUT huge amount of free memory
Date
Msg-id 20130501233707.GD23387@momjian.us
Whole thread Raw
In response to Re: high io BUT huge amount of free memory  (Shaun Thomas <sthomas@optionshouse.com>)
Responses Re: high io BUT huge amount of free memory  (Shaun Thomas <sthomas@optionshouse.com>)
List pgsql-hackers
On Wed, Apr 24, 2013 at 08:39:09AM -0500, Shaun Thomas wrote:
> On 04/24/2013 08:24 AM, Robert Haas wrote:
> 
> >Are you referring to the fact that vm.zone_reclaim_mode = 1 is an
> >idiotic default?
> 
> Well... it is. But even on systems where it's not the default or is
> explicitly disabled, there's just something hideously wrong with
> NUMA in general. Take a look at our numa distribution on a heavily
> loaded system:
> 
> available: 2 nodes (0-1)
> node 0 cpus: 0 2 4 6 8 10 12 14 16 18 20 22
> node 0 size: 36853 MB
> node 0 free: 14315 MB
> node 1 cpus: 1 3 5 7 9 11 13 15 17 19 21 23
> node 1 size: 36863 MB
> node 1 free: 300 MB
> node distances:
> node   0   1
>   0:  10  20
>   1:  20  10
> 
> What the hell? Seriously? Using numactl and starting in interleave
> didn't fix this, either. It just... arbitrarily ignores a huge chunk
> of memory for no discernible reason.

Sorry to be dense here, but what is the problem with that output?  That
there is a lot of memory marked as "free"?  Why would it mark any memory
free?

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +



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