Re: New to PostgreSQL, performance considerations

From: Ron <rjpeace(at)earthlink(dot)net>
To: Alexander Staubo <alex(at)purefiction(dot)net>
Cc: Postgresql Performance list <pgsql-performance(at)postgresql(dot)org>
Subject: Re: New to PostgreSQL, performance considerations
Date: 2006-12-15 00:16:42
Message-ID: E1Gv0ko-0004Ht-Jx@elasmtp-scoter.atl.sa.earthlink.net
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At 05:39 PM 12/14/2006, Alexander Staubo wrote:
>On Dec 14, 2006, at 20:28 , Ron wrote:
>
>>Can you do runs with just CFLAGS="-O3" and just CFLAGS="-msse2 -
>>mfpmath=sse -funroll-loops -m64 - march=opteron -pipe" as well ?
>
>All right. From my perspective, the effect of -O3 is significant,
>whereas architecture-related optimizations have no statistically
>significant effect.

Is this opinion? Or have you rerun the tests using the flags I
suggested? If so, can you post the results?

If "-O3 -msse2 - mfpmath=sse -funroll-loops -m64 - march=opteron
-pipe" results in a 30-40% speed up over "-O0", and
" -msse2 - mfpmath=sse -funroll-loops -m64 - march=opteron -pipe"
results in a 5-10% speedup, then ~ 1/8 - 1/3 of the total possible
speedup is due to arch specific optimizations.

(testing "-O3" in isolation in addition tests for independence of
factors as well as showing what "plain" "-O3" can accomplish.)

Some might argue that a 5-10% speedup which represents 1/8 - 1/3 of
the total speedup is significant...

But enough speculating. I look forward to seeing your data.

Ron Peacetree

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