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I recall a reference on the list indicating that newer Xeon processors
don't suffer from the context switching problem reported last year.

In searching the archives, I can't find any specific info indentifying
which Xeon processors don't have this problem.

Anyone point me to a reference?

Is this in any way related to the version of Postgresql one is running?
We're headed for 8, but have a bit of work before we can get there.
We are currently on 7.4.16.

Thanks for any info.
--
Until later, Geoffrey

Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety.
- Benjamin Franklin

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> I recall a reference on the list indicating that newer Xeon processors
> don't suffer from the context switching problem reported last year.
>
> In searching the archives, I can't find any specific info indentifying
> which Xeon processors don't have this problem.
>
> Anyone point me to a reference?

We recently migrated to a woodcrest @ 3 GHz from a 2 Ghz opteron. The
woodcrest seems to be enjoying doing db-related work. I don't have
numbers other than load is much lower now.

> Is this in any way related to the version of Postgresql one is running?
> We're headed for 8, but have a bit of work before we can get there.
> We are currently on 7.4.16.

We are at 7.4.14 which works fine atm.

regards
Claus

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On Fri, Feb 23, 2007 at 02:05:57PM -0500, Geoffrey wrote:
> In searching the archives, I can't find any specific info indentifying
> which Xeon processors don't have this problem.

AFAIK the cut-off point is at the Woodcrests. They are overall much better
suited to PostgreSQL than the older Xeons were.

It's slightly unfortunate that AMD and Intel cling to the Opteron and Xeon
names even though they're making significant architecture changes, but that's
life, I guess.

/* Steinar */
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Homepage: http://www.sesse.net/

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Steinar H. Gunderson wrote:
> On Fri, Feb 23, 2007 at 02:05:57PM -0500, Geoffrey wrote:
> > In searching the archives, I can't find any specific info indentifying
> > which Xeon processors don't have this problem.
>
> AFAIK the cut-off point is at the Woodcrests. They are overall much better
> suited to PostgreSQL than the older Xeons were.
>
> It's slightly unfortunate that AMD and Intel cling to the Opteron and Xeon
> names even though they're making significant architecture changes, but that's
> life, I guess.

AFAIR Intel has been calling their server processors Xeon since Pentium
Pro's, at least.

--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.

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On Fri, Feb 23, 2007 at 04:53:18PM -0300, Alvaro Herrera wrote:
>> It's slightly unfortunate that AMD and Intel cling to the Opteron and Xeon
>> names even though they're making significant architecture changes, but that's
>> life, I guess.
> AFAIR Intel has been calling their server processors Xeon since Pentium
> Pro's, at least.

Yes, that was sort of my point. :-)

/* Steinar */
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Geoffrey,

> I recall a reference on the list indicating that newer Xeon processors
> don't suffer from the context switching problem reported last year.

Just to be clear, it's a software problem which affects all architectures,
including AMD and Sparc. It's just *worse* on the PIII and P4 generation
Xeons.

--
--Josh

Josh Berkus
PostgreSQL @ Sun
San Francisco

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Josh Berkus wrote:
> Geoffrey,
>
>> I recall a reference on the list indicating that newer Xeon processors
>> don't suffer from the context switching problem reported last year.
>
> Just to be clear, it's a software problem which affects all architectures,
> including AMD and Sparc. It's just *worse* on the PIII and P4 generation
> Xeons.

Thanks, that's what I need to hear. They've since cut a deal for
Operton based hardware, so the point is now moot.

--
Until later, Geoffrey

Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety.
- Benjamin Franklin

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Josh Berkus wrote:
> Geoffrey,
>
>> I recall a reference on the list indicating that newer Xeon processors
>> don't suffer from the context switching problem reported last year.
>
> Just to be clear, it's a software problem which affects all architectures,
> including AMD and Sparc. It's just *worse* on the PIII and P4 generation
> Xeons.
>

Also isn't it pretty much *not* a problem with current versions of
PostgreSQL?

Joshua D. Drake

--

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Joshua D. Drake wrote:
> Josh Berkus wrote:
>> Geoffrey,
>>
>>> I recall a reference on the list indicating that newer Xeon processors
>>> don't suffer from the context switching problem reported last year.
>> Just to be clear, it's a software problem which affects all architectures,
>> including AMD and Sparc. It's just *worse* on the PIII and P4 generation
>> Xeons.
>>
>
> Also isn't it pretty much *not* a problem with current versions of
> PostgreSQL?

As I've heard. We're headed for 8 as soon as possible, but until we get
our code ready, we're on 7.4.16.

--
Until later, Geoffrey

Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety.
- Benjamin Franklin

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On 2/23/07, Joshua D. Drake <jd@commandprompt.com> wrote:
> Also isn't it pretty much *not* a problem with current versions of
> PostgreSQL?

We had a really *big* scalability problem with a quad Xeon MP 2.2 and
PostgreSQL 7.4. The problem is mostly gone since we upgraded to 8.1 a
year ago.

Woodcrest seems to perform really well with PostgreSQL according to
what I can read on the Internet so we will probably change the server
for a dual Woodcrest in a few months.

--
Guillaume

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