Re: how to get rid of XFree in the longterm (just a thought)

From: Kip Rugger (kbr_at_pangea.ca)
Date: 03/23/04 

Date: 23 Mar 2004 14:17:55 -0600

Soeren Sandmann <sandmann@daimi.au.dk> wrote:
>There is a scheduler inside the X server too, and that scheduler is
>actually responsible for some of the expose and resize lag that people
>complain about. The problem is that the X scheduler prioritizes the
>clients that are getting input events higher than other
>clients. That's typically good, because clients that are getting input
>events are generally those the user cares about.
>
>However, there is a pathology when you are dragging windows around or
>resizing them, because then the window manager is getting input events
>and other clients aren't, so the X server prioritizes the window
>manager above everything else, and the result is the lagging effects
>where the other clients are having their drawing requests ignored.

Interesting point. The Xserver code has a number of sections surrounded
by #ifdef SMART_SCHEDULE which would appear to implement this behaviour.
This would suggest that the opposite problem -- say a client doing some
form of continuous updating -- could preclude effective user interaction.
After all, you cannot tolerate an application locking out user control.

Maybe SMART_SCHEDULE is not smart enough. It would be interesting to
know the history of this change.

>If you renice the X server to -n, you'll make the problem worse,
>because then the other clients will not even *run* if the X server is
>runnable, which it is all the time when the user is moving windows
>around.

The nice value on must un*x systems is a bias, not an absolute priority.
Thus a small negative nice value would give the server a running start,
but would not preclude other processes from being dispatched if the
server became compute-bound.

I would avoid renice-ing anything to -20 because that is indeed the
situation that you are describing.

Relevant Pages

  • Re: Users Cant Access Documents on Server
    ... my computer to the network on the server. ... Connection Wizard none of the computers were listed. ... The Mac clients can not communicate with the server box. ... > Error Messages When You Open or Copy Network Files on Windows XP SP1 ...
    (microsoft.public.windows.server.sbs)
  • Re: Cannot join Windows 2003 Server to SBS 2000 Domain
    ... this on all client computers at this remote office. ... All the clients but one at the main office are Windows XP Pro. ... > 'adprep' commands on the SBS 2000 server. ...
    (microsoft.public.windows.server.sbs)
  • Re: Users Cant Access Documents on Server
    ... > then add my computer to the network on the server. ... Did you not see the computers in the Server Management taskpad section? ... The Mac clients can not communicate with the server box. ... >> Error Messages When You Open or Copy Network Files on Windows XP SP1 ...
    (microsoft.public.windows.server.sbs)
  • Re: Group Policy Results Wizard
    ... I guess we can rule out Windows ... If you can't reach the WMI from the server you will want to try to reach it ... switching off the Windows Firewall on one of the clients, ... Business Server Windows Firewall" (not Small Business Server ...
    (microsoft.public.windows.server.sbs)
  • Re: Application design question
    ... system where clients can register with the server ... The server would then keep track of these requests and everytime the data ... scheduler component first (one that can fire events based on ...
    (microsoft.public.dotnet.languages.csharp)