From: Ista Zahn <istazahn@gmail.com>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: 21077@debbugs.gnu.org
Subject: bug#21077: 24.5; Slow printing in inferior python buffer with python-shell-enable-font-lock
Date: Fri, 31 Jul 2015 21:46:28 -0400 [thread overview]
Message-ID: <CA+vqiLHBzaff+SJOJvzg1QVdWwmZZy7AWMvt6dU=rwxPugGBwQ@mail.gmail.com> (raw)
In-Reply-To: <jwvzj2c9e76.fsf-monnier+emacsbugs@gnu.org>
On Fri, Jul 31, 2015 at 6:07 PM, Stefan Monnier
<monnier@iro.umontreal.ca> wrote:
>>> As mentioned, font-lock is but one of the parts of Emacs that slow down
>>> as lines get longer.
>> I'm not all that concerned with things slowing down slightly,
>
> Neither am I. All the others I care about also end up rendering
> Emacs unusable. They just show up at different times, or start biting
> you at different line lengths.
>
>>> In the case of comint modes, rather than disable font-lock we should
>>> refrain from font-locking the text after the last \n (since that's the
>>> line that keeps getting expanded, so we end up re-font-locking it O(N)
>>> times for a line of length N, for a total amount of work of O(N^2)).
>>> IIRC I have a similar hack in grep.el or compile.el.
>> OK, but unless there are clear plans to fix this soon the default value of
>> python-shell-enable-font-lock should be changed to nil until such time as a
>> fix is in place.
>
> I disagree. All comint modes suffer from this problem, AFAIK, and
> I don't see why Python programs would be more likely to generate long
> lines than programs in other languages.
Try this with the currently released version of emacs:
1. Start emacs with 'emacs -Q'
2. Type 'M-x ielm' then '(number-sequence 1 9999)'
3. Type 'M-x eshell' then 'number-sequence 1 9999 RET'
4. Type 'M-x shell' then 'python -c "print(list(range(9999)))" RET'
5. Type 'M-x run-python' then 'print(list(range(9999))) RET'
For me 1-3 print relatively quickly, 4 prints relatively slowly, and
_only_ 5 is so slow that I consider it non-functional. This bug report
is about issue 5 above.
Of course if you have a patch to make 4 faster as well that's great.
But 5 is the bug I'm reporting here, and I would really appreciate it
someone would either accept my suggestion for fixing it or provide an
alternative fix that does the job better.
Best,
Ista
>
> But yes, I'd really be happy to see some tentative patch along the lines
> I outlined above.
>
>
> Stefan
next prev parent reply other threads:[~2015-08-01 1:46 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-16 16:42 bug#21077: 24.5; Slow printing in inferior python buffer with python-shell-enable-font-lock Ista Zahn
2015-07-16 18:34 ` Eli Zaretskii
2015-07-16 19:09 ` Ista Zahn
2015-07-16 19:34 ` Eli Zaretskii
2015-07-16 19:50 ` Ista Zahn
2015-07-17 6:53 ` Eli Zaretskii
2015-07-17 8:33 ` Stefan Monnier
2015-07-17 8:56 ` Rasmus
2015-07-29 20:50 ` Ista Zahn
2015-07-30 23:19 ` Stefan Monnier
2015-07-31 0:27 ` Ista Zahn
2015-07-31 22:07 ` Stefan Monnier
2015-08-01 1:46 ` Ista Zahn [this message]
2015-08-01 12:36 ` Wolfgang Jenkner
2015-08-01 16:26 ` Ista Zahn
2015-08-03 23:57 ` Wolfgang Jenkner
2016-07-14 1:31 ` npostavs
2015-08-01 12:42 ` Wolfgang Jenkner
2015-08-03 21:41 ` Stefan Monnier
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