[Xcb] what are "requests that the server can process quickly" ,

Jamey Sharp jamey at minilop.net
Sat Apr 21 14:03:39 PDT 2007


On Sat, Apr 21, 2007 at 09:22:54AM +0200, Vincent Torri wrote:
> in the XCB Notes ...

Vincent's talking about this page:
	http://xcb.freedesktop.org/wiki/XcbNotes

> Question: Can someone give me 2 examples of resquests, one being processed 
> faster by the server than the second ? And if possible, a more accurate 
> definition of the speed of the processing of a request ?

ListFontsWithInfo can take a *really* long time to execute. Of course
nobody should use it for all sorts of reasons anyway, so maybe that's a
bad example.

GetInputFocus should be really fast because it just has to read a global
variable. GetImage is slower because it has to read data back from the
video card, which the hardware is definitely not optimized for.

Rule 1b means that if you need to know which window currently has focus,
and you also need to get the contents of some drawable, you should send
the GetInputFocus request first and force that response first.

For many requests, you can look at x11perf output to get a rough idea of
which is faster.

--Jamey
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