Bugzilla Bug 75254

Some time ago I give a try to mac on linux emulator and discovered that it
generaly works fine but the mouse pointer jumps badly on my MacOSX
installation. Generaly it stops at all system activities (Opening a window for
example)

I made a small investigation and noticed that mol process has nice value set to
-19 (sigh) and this seems to cause my problem. renice mol to -5 for example
cure my problem and mouse works just fine.


Reproducible: Always
Steps to Reproduce:
1.
2.
3.

It seems not only I have similar problem. I was able to help a guy at #mol
channel that can't install MacOS9 because the installator takes 30min's to show
up on his system.

Renice mol to 0 helps.

Currently I change the mol sources and remove all setpriority() calls and it
seems to work just fine. I think this can be related to some recent 2.6.x
scheduler changes.

Created an attachment (id=47842) [edit]
Less intrusive, only removes the main thread priority change

Created an attachment (id=47843) [edit]
Removes all priority changes

I've tested both here, I don't see much of a difference between the two, but
someone else might.  Since I didn't see much of a difference, I'd say go for
the less intrusive patch.  I'm running an nptl glibc, so maybe linuxthreads
reacts differently.  Comments appreciated!

Forgot to mention that I do see the behaviour mentioned in the bug report and
either renicing or removing the priority changes do fix the problem.  I suspect
it's related to the scheduler in 2.6.

Yes this is scheduler for sure

Generaly using O(1) scheduler or staricase scheduler normal apps should not touch nice value at all. It's reserved for system and critical apps.

My system use ntpl and 2.6.9 kernal image too. And remove all setpriorit() calls definitly fix that problem.

------ This note is from starcase scheduler author:

The tuning in the 2.6 kernel scheduler and the staircase scheduler are
specifically designed to not need -ve nice levels for any normal userspace
tasks, but for critical things like root shells to use in case of emergency, or
video and audio capture

Added the patch that removes all priority changes for both versions of mol in
CVS.  Reopen the bug if it's still a problem or if there is a problem with the
fix.  Thanks!