Not to thread the X server

[Juliusz Chroboczek]

> What would be cool would be the ability either to suspend
> a request in the middle of its execution and use a block handler to
> resume it after servicing input events and other clients, or to have
> the main loop delegate the execution of a CPU-bound request to
> a thread pool.

Sorry to reply to myself...  In a previous life, I wrote a DPS
extension for XFree86[1] that worked like that.  The DPS requests
would only stash the code to be executed by the server into
a server-side data structure, and the DPS code was actually executed
in a block handler (with the DPS interpreter yielding to the server's
main event loop very frequently).  The advantage was that execution of
DPS code did not impact the X latency much; but this only worked
because the PS interpreter I used was able to efficiently store all of
its state in a small data structure.

                                        Juliusz

[1] http://dps.sourceforge.net/index-old.html