[debbugs-tracker] bug#29846: closed (scroll and fontify takes longer time for file in slow network)

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Your message dated Thu, 28 Dec 2017 14:03:47 -0500
with message-id <address@hidden>
and subject line Re: bug#29846: scroll and fontify takes longer time for file 
in slow network
has caused the debbugs.gnu.org bug report #29846,
regarding scroll and fontify takes longer time for file in slow network
to be marked as done.

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29846: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=29846
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--- Begin Message --- Subject: scroll and fontify takes longer time for file in slow network Date: Mon, 25 Dec 2017 14:03:43 +0800

Hi,

Windows 7, GNU Emacs 27.0.50 (build 1, x86_64-w64-mingw32) of 2017-12-09.

Issue:

I have remote dirver (//server/path) mapped to my windows system (samba?). The network is slow, and it takes some time to open the file. However, after I have the file opened and scroll down, it takes a long time to scroll to the next screen. It gets worse if the jit-lock-debug-mode is on. After that if I try to scroll back to those has been fontified, it get fluent as expected.

If I open the same file in a local driver (speed is higher than the network definitely), the scroll is very fluent.

If I open a txt file (fundmental-mode, not fontification) in the same remote directory, the scroll actions are fluent as well.

Per my understanding, all actions should be done in memory when a file has been read into buffer, except backup, autosave, etc. The response should not depents on where the file located phically.

How to repeat it:

1. Find a slow transfer rate network (sorry, it may be hard)

2. Prepare a long c file, 3-4 screens.

3. take font-lock-mode on (jit-font-mode)

4. Open the c file and scroll down, scroll down, scroll down...

5. scroll up, scroll up, scroll up

I have tried profiler. It indicates, the jit-font and redisplay take majority of the cpu time.

1. open the c file

2. profiler-start

3. scroll down, scroll down, scroll down...

4. profiler-report

Best Regards,

Shuguang Sun

--- End Message ---

> --- Begin Message ---
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> Subject: 
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> Re: bug#29846: scroll and fontify takes longer time for file in slow network
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> Date: 
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> Thu, 28 Dec 2017 14:03:47 -0500
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> User-agent: 
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> Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux)
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>
> >> I believe this bug was introduced by yours truly
> >> in commit 6bc76cee212aab0a2c02f8c28213fc842cc7880f:
> [...]
> >> And I think the patch below hence belongs in emacs-26.  Any objection?
> > LGTM, please push to emacs-26.
>
> Installed,
>
>
>         Stefan
>
>
> --- End Message ---