Re: iozone write 50% regression in kernel 2.6.24-rc1

[Zhang, Yanmin]

On Mon, 2007-11-12 at 12:25 -0500, Mark Lord wrote:
> Peter Zijlstra wrote:
> ..
> > While I see that the write speed as reported under .24 ~70MB/s is much
> > lower than the one reported under .23 ~200MB/s, I find it very hard to
> > believe my poor single SATA disk could actually do the 200MB/s for
> > longer than its cache 8/16 MB (not sure).
> > 
> > vmstat shows that actual IO is done, even though the whole 512MB could
> > fit in cache, hence my suspicion that the ~70MB/s is the most realistic
> > of the two.
> ..
> 
> Yeah, sequential 70MB/sec is quite realistic for a modern SATA drive.
> 
> But significantly faster than that (say, 100MB/sec +) is unlikely at present.
I just use command '#iozone -i 0 -r 4k -s 512m', no '-e -c'. So if
we consider cache, the speed is very fast. On my machine with 2.6.23, the write speed is
631M/s, quite fast. :)
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