| From: | Jeff Davis <pgsql(at)j-davis(dot)com> |
|---|---|
| To: | Ants Aasma <ants(at)cybertec(dot)at> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Greg Smith <greg(at)2ndquadrant(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Florian Pflug <fgp(at)phlo(dot)org>, Andres Freund <andres(at)2ndquadrant(dot)com>, Bruce Momjian <bruce(at)momjian(dot)us>, Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>, Simon Riggs <simon(at)2ndquadrant(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Enabling Checksums |
| Date: | 2013-04-22 19:22:21 |
| Message-ID: | 1366658541.2646.50.camel@sussancws0025 |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Mon, 2013-04-22 at 19:25 +0300, Ants Aasma wrote:
> I was just now writing up a generic C based patch based on the
> parallel FNV-1a + shift that we discussed with Florian with an added
> round of mixing. Testing the performance in isolation indicates that:
> 1) it is about an order of magnitude faster than the Sarwate CRC
> method used in Postgresql.
> 2) it is about 2x faster than fastest software based CRC method.
> 3) by using -msse4.1 -funroll-loops -ftree-vectorize compilation
> options the performance improves 5x. (within 20% of handcoded ASM)
That's great news!
This means that we can have a simple C implementation in a separate
file, and pass a few build flags when compiling just that file (so it
doesn't affect other code). That should make reviewers/committers happy
(including me).
FWIW, that was my last real concern about FNV (reviewability). I'm not
worried about the performance based on your analysis; nor am I worried
about the error detection rate.
Regards,
Jeff Davis
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Florian Pflug | 2013-04-22 19:32:23 | Re: Enabling Checksums |
| Previous Message | Robert Haas | 2013-04-22 19:19:36 | Re: 9.3 Beta1 status report |