Re: 2.4.0test9 vm: disappointing streaming i/o under load

Hello,

Finally got round to checking out 2.4.0test9.

Unfortunately, 2.4.0test9 exhibits poor streaming i/o performance when
under a bit of memory pressure.

The test is this: boot with mem=32M, log onto GNOME and start xmms playing
a big .wav ripped from a CD (this requires 100-200k read i/o per second).

Then, I start then kill netscape. I then started a find / and started
gnumeric firing up at the same time.

Would you try setting /proc/sys/vm/page-cluster to 8 or 16 and let
me know the results?  I think one _part_ of the problem is that
when the swapper isn't agressive enough, it causes too much disk
thrashing which gets in the way of normal I/O... my experience
has been that with modern disks with 512K+ cache you have to
write in 64K clusters to get optimum throughput.

Eric


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