| From: | Mark Kirkwood <markir(at)paradise(dot)net(dot)nz> |
|---|---|
| To: | PGSQL Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, mark(at)mark(dot)mielke(dot)cc, Gurjeet Singh <singh(dot)gurjeet(at)gmail(dot)com> |
| Subject: | Re: New CRC algorithm: Slicing by 8 |
| Date: | 2006-10-23 10:26:34 |
| Message-ID: | 453C98DA.7040805@paradise.net.nz |
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| Lists: | pgsql-hackers |
Mark Kirkwood wrote:
> Tom Lane wrote:
>> Are you running similar gcc versions on both? I realize I forgot to
>> document what I was using:
> Ah - good point, FreeBSD is using an older compiler:
>
> FreeBSD: gcc (GCC) 3.4.6 [FreeBSD] 20060305
> Linux: gcc (GCC) 4.1.1 (Gentoo 4.1.1)
>
> Hmm - there is a FreeBSD port for 4.1.2, I might set that off to build
> itself and see if compiling with it changes the results any....
>
Here are the results after building gcc 4.1.2 (repeating results for gcc
3.4.6 for comparison). I suspect that performance is probably impacted
because gcc 4.1.2 (and also the rest of the tool-chain) is built with
gcc 3.4.6 - but it certainly suggests that the newer gcc versions don't
like the slice-8 algorithm for some reason.
Std crc Slice-8 crc
Intel P-III 1.26Ghz (FreeBSD 6.2 gcc 3.4.6)
8192 bytes 12.975314 14.503810
1024 bytes 1.633557 1.852322
64 bytes 0.111580 0.206975
Intel P-III 1.26Ghz (FreeBSD 6.2 gcc 4.1.2)
8192 bytes 19.516974 29.457739
1024 bytes 2.448570 3.742106
64 bytes 0.112644 0.335292
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