Re: [HACKERS] Sequential scan speed, mmap, disk i/o

Bruce Momjian <maillist@candle.pha.pa.us>

From: Bruce Momjian <maillist@candle.pha.pa.us>
To: lockhart@alumni.caltech.edu (Thomas G. Lockhart)
Cc: mimo@interdata.com.pl, hackers@postgresql.org, info@bsdi.com
Date: 1998-05-16T04:43:49Z
Lists: pgsql-hackers
> 
> > Basically, Linux is double my speed for 8k mmap'ed chunks.  Around 32k
> > chunks, I get closer, and 8mb chunks are the same.  Glad to hear Linux
> > has optimized mmap() recently, because BSD/OS looks much slower than
> > Linux on this.
> 
> Well Bruce, don't be too happy. Most people aren't yet running the
> optimized kernel; don't know if any of the benchmarks came from someone
> running a bleeding-edge development version, which is what 2.1.99 would
> be; first feature-freeze release in preparation for v2.2 afaik :)
> 
> And scrappy, no need to note that _all_ Linux kernels are bleeding edge
> releases :)

[FYI, BSDI, Linux dev. release is beating BSDI for 8k mmaps() by 2x.]

I must say, when I saw Linux beating BSDI by 2x, I started wondering if
the great BSDI engineers were sleeping or something.  Now that I
understand that this improvement is a somewhat new effort, I feel a
little better.

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