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

Eric Lowe
2000-10-11T11:38:08Z

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