2.5.47 scheduler problems?

Mike Galbraith
2002-11-18T06:17:02Z

Greetings,

For testing swap throughput, I like to run make -j30 bzImage on my 500Mhz
PIII w. 128Mb ram. For testing interactivity, I fire up KDE, start a
smaller make -j, grab a window, and wave it around.

With 2.4.20rc2+rc1aa1, running a -j10 build (not swapping) is very very
bad. However, if I set all tasks in the system to SCHED_FIFO or SCHED_RR
prior to this light make -j, I have a ~pretty smooth system.

If I do the same in 2.5.47, I have no control of my box. Setting all tasks
to SCHED_FIFO or SCHED_RR prior to starting make -j10 bzImage, I can regain
control, but interactivity under load is basically not present.

I used to be able to wave a window poorly at make -j25 (swapping heftily),
fairly smoothly at make -j20, and smoothly at make -j15 or below. This
with no SCHED_RR/SCHED_FIFO. (I haven't done much testing like this in
quite a while though)

-Mike