From: Gavin Hamill <gdh@laterooms.com>
To: Simon Riggs <simon@2ndquadrant.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: pg 8.1.3, AIX, huge box, painfully slow.
Date: Mon, 10 Apr 2006 10:41:42 +0100
Message-ID: <443A2856.6050905@laterooms.com> (raw)
In-Reply-To: <1144661209.21409.131.camel@localhost.localdomain>
References: <C05C3C44.211A5%llonergan@greenplum.com>
<17613.1144451138@sss.pgh.pa.us>
<1144661209.21409.131.camel@localhost.localdomain>
Simon Riggs wrote:
> pSeries cache lines are 128 bytes wide, so I'd go straight to 128.
>
Hello :)
OK, that line of code is:
#define LWLOCK_PADDED_SIZE (sizeof(LWLock) <= 16 ? 16 : 32)
What should I change this to? I don't understand the syntax of the <= 16
? : stuff...
would a simple "#define LWLOCK_PADDED_SIZE 128" be sufficient?
>If you're renting all 8 CPUs, I'd drop to 4 and try that instead. With 8
>CPUs the contention will vary according to what each CPU is doing at any
>one time - when they all hit the contention spot, things will get worse.
>
>
>
We have a physical machine installed in our rack at the data centre,
rather than renting a virtual partition of a real machine... I'm not
sure how to enable/disable CPUs even with the help of 'smitty' :)
>The pSeries has good CPUs and great caching, so I'd expect contention to
>be somewhat more apparent as a bottleneck.
>
>
>
Yep, I expected 32MB of 'L3' cache would yield impressive results :)
Cheers,
Gavin.
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To: pgsql-performance@postgresql.org
Cc: gdh@laterooms.com, simon@2ndquadrant.com
Subject: Re: pg 8.1.3, AIX, huge box, painfully slow.
In-Reply-To: <443A2856.6050905@laterooms.com>
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