Re: Report of performance on Alpha vs. Intel - Mailing list pgsql-general

I'm curious, what OS did you perform these test under?

-Mitch

----- Original Message -----
From: "Steve Wolfe" <steve@iboats.com>
To: <pgsql-general@postgresql.org>
Sent: Tuesday, September 05, 2000 10:14 AM
Subject: [GENERAL] Report of performance on Alpha vs. Intel


>
>    This week, I had the opportunity to compare the performance of
PostgreSQL
> on an Alpha and an Intel server, and the results kind of surprised me.
I'd
> love to hear if this has been the case for others as well...
>
> -------------
> Intel Machine
>
> SuperMicro 8050 quad Xeon server
> 512 MB RAM
> 4 x PII Xeon 400 MHz (secondary cache disabled)
> RAID array w/ 5 9-gig drives
>
> Approximate cost:  $6000
> --------------
> Alpha Machine
> AlphaServer DS20E
> 2 x CPU (500 MHz or 667 MHz)
> 2 GB RAM
> 9-gig SCSI drive
>
> Approximate cost:  $20,000 - $25,000
> -----------------------
>
> General System notes
>
>     I'm not sure which chips the Alpha uses, the 500 MHz or the 667 MHz.
> Also, because the SuperMicro board is meant for the newer Xeons, the
> secondary cache had to be completely disabled on the PII 400 Xeons, so
that
> machine was definitely not running up to potential.
>
> -------------------------
> Test method
>
>    This wasn't exactly the ANSI tests, but it accurately reflected what we
> need out of a machine.  A while back we logged 87,000 individual queries
on
> our production machine, and I selected one thousand distinct queries from
> that.
>
>    On each machine I spawned 20 parallel processes, each performing the
> 1,000 queries, and timed how long it took for all processes to finish.
>
>    To try and keep the disk subsystem from being a factor, this used only
> selects, no updates or deletes.  Also, the database is small enough that
the
> entire thing was easily in the disk cache at all times.
> --------------------------
> Test results
>
>   The Alpha finished in just over 60 minutes, the Xeon finished in just
over
> 90.
>
> -----------------------------
> Test interpretation
>
>   Once I started looking at the numbers, I was suprised.  On a
> processor-for-processor basis, the Alpha was three times as fast as the
> Intels.  However, the Intels that it was pitted against were only 400 MHz
> chips, only PII (not the PIII), *and* had the external cache completely
> disabled.
>
>    So, the Alpha provided three times the performance for four times the
> cost - but if the megabyte of cache had been enabled on the Xeons, I think
> that the results would have been significantly different.  Also, if the
> chips had been even relatively recent chips (say, some 700 or 800 MHz
Xeons)
> with the cache enabled, it's possible that it could have come close to the
> performance of the Alpha, at a much lower cost.
>
>   Overall, I was expecting the Alpha to give the Intel a better trouncing,
> especially considering the difference in cost, but I guess it's hard to
beat
> Intel for transactions/dollar.  If sheer server capacity is the only
> relevant factor, forget Intel (You won't find Intels with 64 processors,
and
> I don't think you'll see them even with the Itaniums).  If your needs are
> more down-to-Earth, they're the best you can get for the money.
>
> steve
>
>
>