ATA disk performance (ICH2 controller), some tests and comparison with Linux 2.6.5

Frode Nordahl frode at
Sat Sep 25 14:42:43 PDT 2004

On Sep 25, 2004, at 22:59, Mauro Triulzi wrote:
> b) Now the same under Linux (kernel 2.6.5)
> Write performance
> linux:/usr # date && dd if=/dev/zero count=1000000 && 
> date
> Sat Sep 25 21:38:30 CEST 2004
> 1000000+0 records in
> 1000000+0 records out
> Sat Sep 25 21:38:35 CEST 2004
> is about 488 MB, rate about 100 MB/sec!!

I'm pretty sure you have more than 488 MB memory, so the data will 
never actually be written to disk during this test. You should write a 
file at least twice the size of your memory, and rerun it three times 
to get any good results, running sync immedialtely after the dd will 
not hurt neither.

In general, your test is obviously run on a disk in a multiboot 
situation, this will not work. As FreeBSD and Linux will be put on 
different parts of the disk which has different characteristics when it 
comes to available performance.

Frode Nordahl

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