Re: Pg+Linux swap use - Mailing list pgsql-performance

For the record I am running on SuSE with a pretty much stock kernel. Not to
sound naïve, but is turning of HT something done in the bios?

Rob

-----Original Message-----
From: pgsql-performance-owner@postgresql.org
[mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Bill Moran
Sent: Friday, October 31, 2003 9:56 AM
To: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Pg+Linux swap use

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@postgresql.org
> [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Andrew
Sullivan
> Sent: Friday, October 31, 2003 8:36 AM
> To: pgsql-performance@postgresql.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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