Re: patch postgresql for AMD64 (Opteron)

Hi Tom,

I remember that you provide a small SQL script to force the context
switch storm. Can you provide a similar script for Pg 8.1.4?

It looks to me that you get context switch storm if you access with
SELECT one table from multiple clients.

I have a customer which has an current XEON MP DualCore and we get
150000+ context switches/sec. We have around 30 clients. We use RHEL 4
in 32-bit (i368) mode. I didn't use the patch for the Opteron-specific
behavior.

Cheers
Sven.

Tom Lane schrieb:
> Sven Geisler <sgeisler(at)aeccom(dot)com> writes:
>> I created a patch for PostgreSQL and x86 architecture.
>> This patch address a Opteron-specific
>> behavior regarding some assembler statements.
>
> AFAICT this patch essentially proposes that we should allow the single
> case of an Opteron running in 32-bit mode to determine our optimization
> strategy for all 32-bit Intel. Tail wagging dog, no?
>
> As the comment notes, it's not real clear that the separate cmpb is a
> win on average, but this case is not the average case I'm interested in.
> If you want to make an argument for removing the cmpb you need to
> provide numbers on mainstream 32-bit platforms.
>
> regards, tom lane

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Sven Geisler <sgeisler(at)aeccom(dot)com> Tel +49.30.5362.1627 Fax .1638
Senior Developer, AEC/communications GmbH Berlin, Germany