From: Pietro Pugni <pietro.pugni@gmail.com>
To: Aidan Van Dyk <aidan@highrise.ca>
Cc: pgsql-performance@postgresql.org
Subject: Re: Can't get Dell PE T420 (Perc H710) perform better than a MacMini with PostgreSQL
Date: Thu, 2 Apr 2015 15:23:37 +0200
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Hi Aidan,
>
> T420
> work_mem = 512MB
>
> MacMini
> work_mem = 32MB
>
> So that is why the T420 does memory sorts and the mini does disk sorts.
>
> I'd start looking at why memory sorts on the T420 is so slow. Check your numa settings, etc (as already mentioned).
>
> For a drastic test, disable the 2nd socket on the dell, and just use one (eliminate any numa/QPI costs) and see how it compares to the no-numa MacMini.
>
the command
dmesg | grep -i numa
doesn’t display me anything. I think T420 hasn’t NUMA on it. Is there a way to enable it from Ubuntu? I don’t have immediate access to BIOS (server is in another location).
For QPI I don’t know what to do. Please, can you give me more details?
> If you want to see how bad the NUMA/QPI is, play with stream to benchmark memory performance.
With stream you refer to this: https://sites.utexas.edu/jdm4372/tag/stream-benchmark/ ? Do you suggest me some way to do this kind of tests?
Thank you very much
Pietro
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To: pgsql-performance@postgresql.org
Cc: pietro.pugni@gmail.com, aidan@highrise.ca
Subject: Re: Can't get Dell PE T420 (Perc H710) perform better than a MacMini with PostgreSQL
In-Reply-To: <2EBBCD54-D3C8-436F-AF73-84EEF258AB70@gmail.com>
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