Re: tweaking MemSet() performance - Mailing list pgsql-hackers

From Andrew Sullivan
Subject Re: tweaking MemSet() performance
Date
Msg-id 20020830080102.B1191@mail.libertyrms.com
Whole thread Raw
In response to Re: tweaking MemSet() performance  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-hackers
On Thu, Aug 29, 2002 at 07:35:13PM -0400, Bruce Momjian wrote:
> Andrew Sullivan wrote:
> > On Thu, Aug 29, 2002 at 01:27:41AM -0400, Neil Conway wrote:
> > > 
> > > Also, if anyone would like to contribute the results of doing the
> > > benchmark on their particular system, that might provide some useful
> > > additional data points.
> > 
> > Ok, here's a run on a Sun E450, Solaris 7.  I presume your "total"
> > time label corresponds to my "real" time.  That's what I'm including,
> > anyway.
> 
> 
> Now, these are unusual results.  In the 64 case, MemSet is dramatically
> slower, and it only starts to win around 512, and seems to speed up
> after that.
> 
> These are strange results.  The idea of MemSet was to prevent the

Yes, I was rather surprised, too.  In fact, the first couple of runs
I thought I must have made a mistake and compiled with (for instance)
MemSet() instead of memset().  But I triple-checked, and I hadn't.

FWIW, here's an example of what I used to call the compiler:

gcc -O2 -DBUFFER_SIZE=1024 -Ipostgresql-7.2.1/src/include/ memset.c

A
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Andrew Sullivan                         204-4141 Yonge Street
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<andrew@libertyrms.info>                              M2P 2A8                                        +1 416 646 3304
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