Re: Cost of XLogInsert CRC calculations

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Manfred Koizar <mkoi-pg(at)aon(dot)at>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Mark Cave-Ayland <m(dot)cave-ayland(at)webbased(dot)co(dot)uk>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Cost of XLogInsert CRC calculations
Date: 2005-05-17 22:29:54
Message-ID: 200505172229.j4HMTsL27844@candle.pha.pa.us
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Manfred Koizar wrote:
> On Mon, 16 May 2005 12:35:35 -0400, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >Anyone want to try it with non-gcc compilers?
>
> MS VC++ 6.0 with various predefined optimizer settings
>
> 2x32 64
> Default (without any /O) 0.828125 0.906250
> MinSize (contains /O1) 0.468750 0.593750
> MaxSpeed (contains /O2) 0.312500 0.640625
>
> Not that it really matters -- but at least this looks like another hint
> that letting the compiler emulate 64 bit operations on non 64 bit
> hardware is suboptimal.

I don't understand why we are testing 64-bit CRC when I thought we
agreed that 32-bit was good enough for our purposes.

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
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