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SubjectRe: Page cache write performance issue
Nathan Scott wrote:
> On Wed, Oct 13, 2004 at 08:20:41PM -0700, Andrew Morton wrote:
>>Nathan Scott <> wrote:
>>> I just tried switching CONFIG_HIGHMEM off, and so running the
>>> machine with 512MB; then adjusted the test to write 256M into
>>> the page cache, again in 1K sequential chunks. A similar mis-
>>> behaviour happens, though the numbers are slightly better (up
>>> from ~4 to ~6.5MB/sec). Both ext2 and xfs see this. When I
>>> drop the file size down to 128M with this kernel, I see good
>>> results again (as we'd expect).
>>No such problem here, with
>> dd if=/dev/zero of=x bs=1k count=128k
>>on a 256MB machine. xfs and ext2.
> Yup, rebooted with mem=128M and on my box, & that crawls.
> Maybe its just this old hunk 'o junk, I suppose; odd that
> 2.6.8 was OK with this though.

Just out of interest, can you get profiles and a few lines
of vmstat 1 from 2.6.8 and 2.6.9-rc, please?
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