Questions tagged [performance]

is for Emacs performance-related issues. Use additional tags to indicate which aspects of Emacs the performance issue is about: startup, navigation, search, screen updates, compilation, execution, debugging, and so on.

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73
votes
10answers
9k views

How do I prevent extremely long lines making Emacs slow?

I see hugely varied performance depending on how many newlines there are in the file I'm visiting. Here's an example. I have two JSON files: $ wget https://github.com/Wilfred/ReVo-utilities/blob/...
41
votes
3answers
3k views

What can I do to speed up my start-up?

What are some basic things I could do to reduce the start-up time? Is there anything in particular I should pay attention to, for that matter? Note: Startup time can be mitigated by starting Emacs ...
26
votes
4answers
2k views

How do I measure performance of elisp code?

How do I measure the performance of my elisp code? What tools / external packages are available for me to measure time taken? In addition to total time, can I see a profile that shows time taken per-...
14
votes
2answers
2k views

How to prevent slow-down when an inferior processes generates long lines?

I use Emacs with Geiser to hack on some Scheme code. As I'm playing around in the REPL I sometimes evaluate expressions that result in a lot of output, often all on one line. For example, I just ...
42
votes
1answer
14k views

How can I troubleshoot a very slow Emacs?

I am writing a document and I have a problem with Emacs' performance that I think appeared just yesterday. I haven't made any alterations in my init file or installed any new packages. The problem is ...
14
votes
2answers
4k views

Magit extremely slow in Windows. How do I optimize?

I am forced to use Windows 10 for a project. Yes, I would rather use GNU/Linux. To keep my sanity, I've tried to regard Windows as a bootloader for Emacs :) Unfortunately, Magit (one of my favorite ...
9
votes
1answer
696 views

unicode.txt slowness

Moving around point (using the cursor keys) in Xah’s unicode.txt in fundamental-mode is noticeably slower than in an ordinary text file. Are the many non-ASCII characters the issue? Anything else? ...
13
votes
2answers
2k views

practical limits on org-mode file size?

I have an org-mode file that's running around 6,000 lines with a hundred or so top-level headlines. It's started to take around a minute to load or save, and occasionally it sends emacs into the weeds ...
8
votes
1answer
302 views

Speed up org-map-entries when matching by property

Question: Why is org-map-entries property matching so slow, and what can I do to speed it up? Background: I have a relatively simple use for org-map-entries: grab the effort (in integer minutes) from ...
8
votes
1answer
1k views

“Making tag completion table” Freezes/Blocks — how to disable

TLDR: I've got a large tags file that loads multiple times per session, making it unusable. Can't find the source of issue or how to disable it -- main goal is to jump to tags, but completion would ...
8
votes
3answers
2k views

Emacs on Windows 7 very slow when computer is outside company network

I'm using GNU Emacs 24.3 on Windows 7 and normally I don't have any problems with speed/responsiveness. I'm launching Emacs with runemacs.exe However, when I am travelling and try to connect to my ...
10
votes
1answer
195 views

Are there any pre-existing benchmark suites for Emacs itself?

(This question is not about writing benchmarks/profiling elisp code, for that, see this question.) Do any benchmark suites exist for Emacs performance? I'm looking for something equivalent to the V8 ...
2
votes
1answer
212 views

Size of process output sent to filter functions

I'm using comint to communicate with a REPL. From time to time the REPL sends large amounts of data. This causes a significant lag (about one second), because my filter function gets called on a ...
2
votes
1answer
456 views

Magit commit is slow even for tiny changes

For the last few months, committing even tiny changes using magit (c c) is really slow to bring up the commit message buffer. I've profiled the code that is executing during that time but I'm not ...