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Re: Pg+Linux swap use

From: Bill Moran <wmoran(at)potentialtech(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Pg+Linux swap use
Date: 2003-10-31 15:55:33
Message-ID: 3FA285F5.6020408@potentialtech.com (view raw or flat)
Thread:
Lists: pgsql-performance
Just for an additional viewpoint.  I'm finishing up a project based on FreeBSD
and PostgreSQL.  The target server is a Dual 2.4G Intel machine.  I have tested
the application with hyperthreading enabled and disabled.  To all appearances,
enabling hyperthreading makes the box act like a quad, with the expected increase
in processing capability - _for_this_application_.

I have also heard the claims and seen the tests that show hyperthreading
occasionally decreasing performance.  I think in the end, you just have to
test your particular application to see how it reacts.

Rob Sell wrote:
> Not being one to hijack threads, but I haven't heard of this performance hit
> when using HT, I have what should all rights be a pretty fast server, dual
> 2.4 Xeons with HT 205gb raid 5 array, 1 gig of memory. And it is only 50% as
> fast as my old server which was a dual AMD MP 1400's with a 45gb raid 5
> array and 1gb of ram. I have read everything I could find on Pg performance
> tweaked all the variables that were suggested and nothing. Which is why I
> subscribed to this list, just been lurking so far but this caught my eye. 
> 
> Rob
> 
> -----Original Message-----
> From: pgsql-performance-owner(at)postgresql(dot)org
> [mailto:pgsql-performance-owner(at)postgresql(dot)org] On Behalf Of Andrew Sullivan
> Sent: Friday, October 31, 2003 8:36 AM
> To: pgsql-performance(at)postgresql(dot)org
> Subject: Re: [PERFORM] Pg+Linux swap use
> 
> On Fri, Oct 31, 2003 at 12:03:59PM -0200, alexandre :: aldeia digital wrote:
> 
>>Scott, Jeff and Shridhar:
>>
>>1 GB RAM :)
>>
>>The stock kernels are not the same, HyperThreading enabled. 80
> 
> 
> Some people have reported that things actually slow down with HT
> enabled.  Have you tried turning it off?
> 
> A
> 


-- 
Bill Moran
Potential Technologies
http://www.potentialtech.com


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