since Postgres is one process/client, It depends on what folks are doing.

And, how smart the scheduling algorithms within your OS are.

LER


--On Wednesday, July 16, 2003 03:46:27 +0200 Mendola Gaetano 
<mendola@bigfoot.com> wrote:

> Hi all,
> we are going to move our production postgres box ( on Linux )
> in a new machine, I'm wondering if I shall leave the Hyperthreading
> feature on or disable it.
> Anyone have experience on this?
>
>
> Thank you in advance
> Gaetano
>
>
> PS: Is really faster postgresql compiled with Intel compiler ?
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 5: Have you checked our extensive FAQ?
>
>                http://www.postgresql.org/docs/faqs/FAQ.html
>



-- 
Larry Rosenman                     http://www.lerctr.org/~ler
Phone: +1 972-414-9812                 E-Mail: ler@lerctr.org
US Mail: 1905 Steamboat Springs Drive, Garland, TX 75044-6749




Tue, 15 Jul 2003 18:54:21 -0500
Larry Rosenman <ler@lerctr.org>
Re: Hyperthreading or not?
Gaetano

> Hi all,
> we are going to move our production postgres box ( on Linux ) 
> in a new machine, I'm wondering if I shall leave the Hyperthreading
> feature on or disable it.
> Anyone have experience on this?

I have been running Postgres on an SMP MIPS machine for quite
a while. I haven't been trying to make it work hard so I can
only attest to the fact that it runs without fault. So yes,
leave the hyperthreading enabled and enjoy.

> PS: Is really faster postgresql compiled with Intel compiler ?

One of my colleagues has been doing some experiments. It seems
that the code generated by the Intel compilers is a bit faster
than gcc.

Warwick
> -- 
> Warwick Hunter                    Agile TV Corporation
> Voice: +61 7 5584 5912            Fax: +61 7 5575 9550
> mailto:whunter@agile.tv           http://www.agile.tv


16 Jul 2003 11:42:09 +1000
Warwick Hunter <whunter@agile.tv>
Re: Hyperthreading or not?
Hi all,
we are going to move our production postgres box ( on Linux ) 
in a new machine, I'm wondering if I shall leave the Hyperthreading
feature on or disable it.
Anyone have experience on this?


Thank you in advance 
Gaetano


PS: Is really faster postgresql compiled with Intel compiler ?


Wed, 16 Jul 2003 03:46:27 +0200
"Mendola Gaetano" <mendola@bigfoot.com>
Hyperthreading or not?
Mendola Gaetano wrote:
> Hi all,
> we are going to move our production postgres box ( on Linux ) 
> in a new machine, I'm wondering if I shall leave the Hyperthreading
> feature on or disable it.
> Anyone have experience on this?

Just FYI.

We turned Hyperthreading off for our production *dual* Xeon box. This is 
mainly because we're on Linux 2.4.9 (+ Red Hat's patches for Advanced 
Server). We've yet to see conclusive evidence that Linux 2.4.9 can take 
dual Hyperthreaded processors into account, therefore we disabled it.

Please note emphasis on DUAL Hyperthreaded processors. If we have 
processors A and B, Linux will see it as, say, A1, A2, B1, B2. We can't 
tell if this version of Linux will not try to run two 100% CPU bound 
processors on A1, and A2, while letting real processor B idle.

Didn't matter much in the end anyway, because postgresql handled our 
load just fine on two real processors.

-- 
Linux homer 2.4.18-14 #1 Wed Sep 4 13:35:50 EDT 2002 i686 i686 i386 
GNU/Linux
  10:30am  up 202 days,  1:35,  6 users,  load average: 5.40, 5.14, 5.05
Wed, 16 Jul 2003 10:55:20 +0800
Ang Chin Han <angch@bytecraft.com.my>
Re: Hyperthreading or not?
On Wed, 16 Jul 2003, Mendola Gaetano wrote:

> Hi all,
> we are going to move our production postgres box ( on Linux ) 
> in a new machine, I'm wondering if I shall leave the Hyperthreading
> feature on or disable it.

The newer kernels are hyper-threading aware.  No idea how much faster that 
might make things for a postgresql server though.

> Anyone have experience on this?

Nope, but I will this fall.

> PS: Is really faster postgresql compiled with Intel compiler ?

Note that since most people use gcc, any problems caused by the Intel 
compiler might take more time to get fixed.


Wed, 16 Jul 2003 09:07:02 -0600 (MDT)
"scott.marlowe" <scott.marlowe@ihs.com>
Re: Hyperthreading or not?
On 16 Jul 2003 at 9:07, scott.marlowe wrote:
> > PS: Is really faster postgresql compiled with Intel compiler ?
> 
> Note that since most people use gcc, any problems caused by the Intel 
> compiler might take more time to get fixed.

Last I heard was that gcc was pretty neck to neck with intel compiler with gcc 
3.2.2 or later. Besides intel compiler yield performance gain on CPU intesive 
applications such as mathematical calculations and as such.

While it would provide some performance benefit, I doubt how much and in how 
many cases for a database app. like postgresql. It's not a CPU hog in the first 
place, most of the times.

Bye
 Shridhar

--
Bones: "The man's DEAD, Jim!"


Wed, 16 Jul 2003 20:56:38 +0530
"Shridhar Daithankar" <shridhar_daithankar@persistent.co.in>
Re: Hyperthreading or not?