Wasn't the context switching issue occurring in specific cases only?
I haven't seen any benchmarks for a 50% performance difference. Neither
have I seen any benchmarks of pure disk IO performance of specific
models of Dell vs HP or Sun Opterons.
Thanks,
Anjan
-----Original Message-----
From: John A Meinel [mailto:john@arbash-meinel.com]
Sent: Monday, May 09, 2005 11:22 AM
To: Anjan Dave
Cc: Geoffrey; Mischa Sandberg; pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Whence the Opterons?
Anjan Dave wrote:
> You also want to consider any whitebox opteron system being on the
> compatibility list of your storage vendor, as well as RedHat, etc.
With
> EMC you can file an RPQ via your sales contacts to get it approved,
> though not sure how lengthy/painful that process might be, or if it's
> gonna be worth it.
>
> Read the article devoted to the v40z on anandtech.com.
>
> I am also trying to get a quad-Opteron versus the latest quad-XEON
from
> Dell (6850), but it's hard to justify a difference between a 15K dell
> versus a 30k v40z for a 5-8% performance gain (read the XEON Vs.
Opteron
> Database comparo on anandtech.com)...
>
> Thanks,
> Anjan
>
15k vs 30k is indeed a big difference. But also realize that Postgres
has a specific benefit to Opterons versus Xeons. The context switching
storm happens less on an Opteron for some reason.
I would venture a much greater benefit than 5-8%, more like 10-50%.
John
=:->