Re: Slow response to keypresses in xorg-server-1.8.0-1

[Andy Koppe <andy dot koppe at gmail dot com>]

On 7 August 2010 23:07, Jon TURNEY wrote:
> Hmmm, looking again at the implementation of select(), I don't immediately
> see that when waiting on /dev/windows, it checks that the message queue has
> old messages on it before waiting. ÂThe MSDN documentation for
> MsgWaitForMultipleObjects() seems to says that messages which had arrived
> before the last PeekMessage() etc. aren't considered new and so don't end
> the wait?

I think you're right, a call to PeekMessage is needed for proper
select() semantics: it shouldn't block if data is available for
reading.

I think it's a good idea anyway though to drain the message queue
before invoking select() on /dev/windows, except if there's a
possibility that message handling blocks out events on other files for
too long. That's because select() has a lot more overhead than
PeekMessage.

Andy

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