Re: CUDA Sorting - Mailing list pgsql-hackers

From Greg Smith
Subject Re: CUDA Sorting
Date
Msg-id 4E779351.10409@2ndQuadrant.com
Whole thread Raw
In response to Re: CUDA Sorting  (Thom Brown <thom@linux.com>)
Responses Re: CUDA Sorting
List pgsql-hackers
On 09/19/2011 10:53 AM, Thom Brown wrote:
> But couldn't that also be seen as a chicken/egg situation?


The chicken/egg problem here is a bit deeper than just "no one offers 
GPUs because no one wants them" on server systems.  One of the reasons 
there aren't more GPUs in typical database server configurations is that 
you're already filling up some number of the full size slots, and 
correspondingly the bandwidth available to cards, with disk 
controllers.  It doesn't help that many server class motherboards don't 
even have a x16 PCI-e slot on them, which is what most GPUs as delivered 
on regular consumer video cards are optimized for.

> But nVidia does produce a non-graphics-oriented GPGPU line called
> Tesla dedicated to such processing.
>    

Tesla units start at around $1500 USD, which is a nice budget to spend 
on either more RAM (to allow higher work_mem), faster storage to store 
temporary files onto, or a faster CPU to chew through all sorts of tasks 
more quickly.  The Tesla units are easy to justify if you have a serious 
GPU-oriented application.  The good bang for the buck point with CPU 
sorting for PostgreSQL is probably going to be a $50-$100 video card 
instead.  For example, the card Vitor is seeing good results on costs 
around $60.  (That's also a system with fairly slow RAM, though; it will 
be interesting to see if the gain holds up on newer systems.)

-- 
Greg Smith   2ndQuadrant US    greg@2ndQuadrant.com   Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support  www.2ndQuadrant.us



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