Messages in this thread | | | Date | Thu, 13 Nov 2003 22:11:23 +1100 | From | Nick Piggin <> | Subject | Re: 2.6 scheduler and "fast user switching" |
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Guy wrote:
>Scenario: > >I typically log in as 'root' on the first console. I then invoke >fluxbox as the GUI. > ># XSESSION=fluxbox startx -- :0 > >I then ctl-alt-F2 another console and login as 'user1'. I then >invoke KDE as the GUI. > >$ XSESSION=kde-3.1.4 startx -- :1 > >I may or may not ctl-alt-Fn and login as 'usern' and repeat the >process. > >Several thoughts: > >1} I've seen Nick Piggin's suggestion of nicing X server to -10. >At the moment, the only way I know to do this is something like > ># XSESSION=fluxbox nice --adjustment=-10 startx -- :N >
If you're not using my patches then nice causes scheduling latency problems so don't do this even if you can. Con's scheduler work actually makes interactivity good at the default priority.
> >A} My default security is that only 'root' can perform nice with >negative values. I am reluctant to play with security for such a >crticial command. >
Debian does this for you. I guess X runs as suid root anyway so its not a big security problem.
> >B} All child threads inherit the new nice value. So in the example >just above, this means all applications started from the GUI >desktop run at a nice value of -10. I believe enhancing the X >server nice value this way defeats the purpose of nicing it to >begin with. Obviously, despite my readings and attempts at >research, I'm must be missing something here. >
Debian manages to only renice the X server. If something like this were required in a distro kernel I guess they would do it for you nicely.
> >2} I expect to travel down to Florida for Xmass to visit family. >One of the things I had hoped to do was to set up my mother's >computer as an X server and hang a thin client terminal {read: >older PC} off of it. This would allowed my mother and brother to >share a reasonably modern system at the same time. > >This is not me just being cheap. I'm interested in setting up >diskless workstations aound a good central X server. I see such >setups as appropriate for a number of situations. If the X server >requires 'nicing' in a single user environment, what happens in >an LTSP environment? >
I think the server runs on the clients... or something ;)
> >My base reference environment is 2.4.20. I still actively use it >for everything I do as everything works as expected. > >Despite my enthusiasm for 2.6, I find it difficult to get >everything to 'just work'. I still see problems in the area of >nForce based mobos {stupid proprietary nVidia!}, broken BIOSes, >and scheduler issues like the above. >
Obviously make sure all your software is up to date with Documentation/Changes, and remember we can't help with closed drivers. If you still have problems please send in a report. Hope this helps
Nick
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