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Bug 75254 - MOL has too high nice value
Summary: MOL has too high nice value
Status: RESOLVED FIXED
Alias: None
Product: Gentoo Linux
Classification: Unclassified
Component: Current packages (show other bugs)
Hardware: PPC Linux
: High normal (vote)
Assignee: PPC Porters
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2004-12-21 16:14 UTC by Marcin Kurek
Modified: 2005-01-27 10:17 UTC (History)
0 users

See Also:
Package list:
Runtime testing required: ---


Attachments
Less intrusive, only removes the main thread priority change (mol-0.9.70-nopriority.patch,429 bytes, patch)
2005-01-07 05:34 UTC, Joe Jezak (RETIRED)
Details | Diff
Removes all priority changes (mol-0.9.70-nopriority2.patch,1.81 KB, patch)
2005-01-07 05:37 UTC, Joe Jezak (RETIRED)
Details | Diff

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Description Marcin Kurek 2004-12-21 16:14:41 UTC
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.
Comment 1 Marcin Kurek 2004-12-31 06:40:25 UTC
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.
Comment 2 Joe Jezak (RETIRED) gentoo-dev 2005-01-07 05:34:38 UTC
Created attachment 47842 [details, diff]
Less intrusive, only removes the main thread priority change
Comment 3 Joe Jezak (RETIRED) gentoo-dev 2005-01-07 05:37:37 UTC
Created attachment 47843 [details, diff]
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!
Comment 4 Joe Jezak (RETIRED) gentoo-dev 2005-01-07 05:40:33 UTC
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.
Comment 5 Marcin Kurek 2005-01-16 15:42:24 UTC
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
Comment 6 Joe Jezak (RETIRED) gentoo-dev 2005-01-27 10:17:39 UTC
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!