Re: [xougen] Preemptible X ?

[Eric Anholt]

On Sun, 2003-08-31 at 07:38, Yaroslav Rastrigin wrote:
> Hi everybody !
> 
> I'm trying to understand some basic principles of X implementation, and now I 
> have a question:
> Basically, X is client-server architecture, so X server is mostly sitting in 
> select() on a number of sockets. After select() returning >0 X reads request 
> from the socket, handles it and sends the reply back. Then, if select() 
> returns more than one socket whose state was changed (iow, more than one 
> client sent a request), will X server handle these requests in parallel, or 
> it will process them one-by-one ? So, if, f.e. XMMS is displaying 
> oscilloscope with full refresh (50 FPS), and I'm moving a window (and it's a 
> bunch of events), does it means that move steps will be intermixed with 
> oscilloscope redraws ?
> Or I'm wrong and some kind of preemptivity mechanism is in place ?

I'm no expert on this, but from what I understand the XFree86 X Server
takes in requests small parts at a time, rotating through clients with
available data.  Eveything is serialized, but the size of the slices
taken is hopefully small enough to provide interactivity but large
enough to keep cache issues minimized.

-- 
Eric Anholt                                address@hidden          
http://people.freebsd.org/~anholt/         address@hidden