Re: making window managers faster

One of the things we did early in X was put an upper bound
on the rate of mouse motion events; this was as much to constrain
network traffic as for interactivity, but setting an upper
limit to around 100hz would probably be a good idea.  One
thing that has mitigated against this is that certain operating
systems haven't rescheduled all that frequently (until recently
Linux was in this catagory), which mitigated against this approach
(since we need some event to force a rescedule).  Going alot faster
is, if anything, going to cause some apps to be less responsive
as they will do more work than they otherwise should.

That is why the X protocol has mouse motion buffers as well:
so that applications that need fine path information can get it
even if the event rate is more modest.

And yes, Raster, you are entirely correct that there are also alot of 
broken window managers written by clueless people.
				- Jim

> Sender: [email protected]
> From: Jouni Tulkki <[email protected]>
> Date: Sat, 26 Oct 2002 16:27:05 +0300 (EET DST)
> To: [email protected]
> Subject: [Render] making window managers faster
> -----
> I have seen people complaining about slow window redraw when moving/resizing
> windows. I had noticed this problem myself and have found one way to reduce
> it.
> X server sends a lot of mouse events when moving the mouse. I haven't
> calculated
> how much but it could be something like 100 - 200 or more per second. This is
> way too much for window moving.
> 
> The solution is to add a time check to the window manager that makes sure that
> windows are not moved more often then (for example) 50 times per second. Same
> applies to window resize, but because window resize is more expensive the
> maximum refresh rate should be lower, maybe about 25 1/s.
> 
> Jouni
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--
Jim Gettys
Cambridge Research Laboratory
HP Labs, Hewlett-Packard Company
[email protected]