Re: 2.6.0-test6 scheduling(?) oddness

bill davidsen
2003-10-01T21:57:01Z

In article <20031001051008.GD1416@Master>,
Murray J. Root <murrayr@brain.org> wrote:
| On Tue, Sep 30, 2003 at 09:55:12PM -0700, Andrew Morton wrote:
| > "Murray J. Root" <murrayr@brain.org> wrote:
| > >
| > > The render finishes in the same 30 minutes, then oowriter starts.
| > > oowriter takes about 3 seconds to load if no rendering is going on.
| >
| > OpenOffice uses sched_yield() in strange ways which causes it to
| > get hopelessly starved on 2.6 kernels. I think RH have a fixed version,
| > but I don't know if that has propagated into the upstream yet.
| >
| > So... Don't worry about OpenOffice too much. Is the problem reproducible
| > with other applications?
|
| Nope - even tried it with KDE apps.
| Write it off to OpenOffice, not test6.

I wish I could just write off programs like that, but if a program is
running, and doing legitimate system calls, and it stops running
(totally or usefully), I'd like to be sure that the kernel doesn't have
some unintended behaviour before I just pass on the program.

Particularly when OO is what allows lots of people to avoid running that
other operating system.

|
| That doesn't explain the major time increase of the render, though.
| 200% for 2.5.65 vs 2.6.0-test6 or 150% for 2.6.0-test5 vs 2.6.0-test6 is a
| bit extreme.

The vmstat sure didn't show a big increase in contenxt switches, but if
there's nothing elese wanting the CPU I would expect the render to be
what's running, and at the same speed as test5.

Suggestion: could you run 'top' in the text output mode to see if for
some reason the CPU is going to some odd process. The revised nice
handling can't make a user process lower priority than the idle loop or
something odd like that, can it?
--
bill davidsen <davidsen@tmr.com>
CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.