Re: Long delay when using undo/redo in eclipse with Cygwin/X

[Jon TURNEY <jon.turney@dronecode.org.uk>]

On 12/06/2013 23:33, Matt D. wrote:
> I'm not sure if this is the appropriate place to direct this question.
> Although the only case where I experience this is in eclipse, it only occurs
> when connecting to a remote X server.
> 
> When using ctrl-z (undo) and ctrl-shift-z (redo) in eclipse there is a
> significant delay in the X session where it appears to 'hang' for several
> seconds. Holding down ctrl-z causes the hangs to queue and can be seen by the
> carrot only being updated when the text area is clicked in between each hang.
> 
> The delay does NOT occur when eclipse is run locally on the machine; it only
> occurs with a remote X session. The X session is done over LAN so there is
> plenty of bandwidth available.
> 
> A delay does NOT occur when doing large amounts of drawing in the text area,
> such as ctrl-a (select-all), very large cuts (ctrl-x), or pasts (ctrl-v).
> 
> The delay does not appear to have any correlation to the size of the task
> being undone/redone. Undo on a single character has the same long delay as
> using undo after deleting everything in a source file.
> 
> The delay still occurs when using undo from the edit menu or after having been
> rebound to another key (ctrl-r for example).
> 
> Any suggestions?

There are a couple of things you might try to isolate the problem:

- try running the X server with -noclipboard to rule out any interaction with
the Windows clipboard integration.
- try a remote X server running on Linux, not Windows

If it behaves the same in both those cases, it looks like something Eclipse is
doing (perhaps requiring excessive round-trips to the server) and a wireshark
capture might be informative.

-- 
Jon TURNEY
Volunteer Cygwin/X X Server maintainer

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