Slow XQueryPointer?

[Lauri Kasanen]

Hi

@Alan:
> You don't have to convert the entire app to XCB to be able to use it for
> just one or two calls, for example, most of xdpyinfo uses libX11 calls
> still, but the loop to list extensions uses xcb to be able to send all
> the queries and then wait for all the responses instead of doing a
> blocking call for every single extension:

Yes, but then I'd depend on libxcb (or have to dive into dlopen and friends).

> Simplest thing (although kind of hideous) might be to launch another
> thread with its own Display connection and only ever run XQueryPointer
> from that, save the coordinates in some shared variable protected by a
> mutex, and read from that in the main thread.  Or in a separate process
> over a pipe, if you don't like threads.
> 
> I don't really know what you need the result for, though, so I don't
> know if that's a viable technique for you.

It's used once per frame for 3d movement (yeh, game). A thread might work.


Attaching a bench app I've used in tracking this down. Run it with some apps open (browser, IRC client, some terminals...) and watch the max number.
Perhaps it'll help, I don't remember how long running a x11perf test took.

-- 
- Lauri
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