[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
bug#42490: Emacs is very slow when navigating into a specific C++ file
From: |
Mattias Engdegård |
Subject: |
bug#42490: Emacs is very slow when navigating into a specific C++ file |
Date: |
Fri, 24 Jul 2020 18:46:45 +0200 |
Hello Olivier,
Thanks for the report! Could you try Emacs 27 (or git master), building from
source if necessary? Those versions should be slightly faster, although the
response time is probably well below acceptable.
If we distill the essentials of your file to some sort of benchmark, we might
end up with:
(with-temp-buffer
(c++-mode)
(dotimes (_ 1000)
(insert "OP(ed,b0) { ldir(); } /* LDIR */\n"))
(garbage-collect)
(let ((t0 (current-time)))
(font-lock-ensure (point-min) (point-max))
(time-to-seconds (time-since t0))))
Emacs 26.3 runs it in 11.9 s on this old lappy, but Emacs 27 does it in 3.3 s.
This is a clear improvement but we should be able to do better. Alan may have a
feeling for where the cycles are spent.