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bug#21473: 24.5; very slow tooltip display to sort-of-slow remote displa
From: |
Eli Zaretskii |
Subject: |
bug#21473: 24.5; very slow tooltip display to sort-of-slow remote display |
Date: |
Tue, 15 Sep 2015 17:32:07 +0300 |
> From: Ken Raeburn <raeburn@permabit.com>
> Date: Mon, 14 Sep 2015 04:13:41 -0400
>
> I’ve noticed that when I’m using a “slow” network link — high bandwidth but a
> round-trip time of 30-40 milliseconds (remember when that was fast?) — the
> tooltip window that pops up when I move the mouse, say, over the buffer name
> in the mode line, takes much longer to come up than when I’m running Emacs on
> a local display. And if I keep moving the mouse around, I’m likely to get the
> tooltip for the buffer-name part of the mode line, but displayed somewhere
> else entirely, depending where the mouse has moved to.
>
> Based on some earlier investigations, I used gdb to look at calls to _XReply
> in the Xlib library; this is the routine that flushes the outgoing buffer to
> the X server and then waits for a response, which contains color info or font
> info or whatever else is wanted by the caller. It’s of interest because each
> such call is going to require a round trip to the X server, and on a
> connection like mine, will add 30ms of delay that cannot be removed without
> eliminating some of the synchronous Xlib calls — e.g., fewer font queries or
> whatever. Of course they can’t all be removed, but if some are pointless or
> redundant we may be able to reduce the time spent waiting.
Is there something new in what you discovered, given the fact that a
tooltip is just a special kind of frame, and so everything that you
reported which causes slow creation of a new frame pertains also to
tooltips?
Thanks.