Re: Cost of XLogInsert CRC calculations

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Mark Cave-Ayland" <m(dot)cave-ayland(at)webbased(dot)co(dot)uk>
Cc: "'Manfred Koizar'" <mkoi-pg(at)aon(dot)at>, "'Greg Stark'" <gsstark(at)mit(dot)edu>, "'Bruce Momjian'" <pgman(at)candle(dot)pha(dot)pa(dot)us>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Cost of XLogInsert CRC calculations
Date: 2005-05-27 14:00:27
Message-ID: 14334.1117202427@sss.pgh.pa.us
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"Mark Cave-Ayland" <m(dot)cave-ayland(at)webbased(dot)co(dot)uk> writes:
> Opt 32 32a 32b 2x32 64 64a 64b
> --------------------------------------------------------
> O1 4.91 4.86 5.43 6.00 11.4 11.39 11.39
> O2 4.96 4.94 4.69 5.18 15.86 18.75 24.73
> O3 4.82 4.83 4.64 5.18 15.14 13.77 14.73

Not sure I believe these numbers. Shouldn't 2x32 be about twice as slow
as just one 32-bit CRC?

regards, tom lane

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