--- Begin Message ---
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Subject: |
29.0.50; cc-mode fontification makes CPU at 100% |
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Date: |
Sat, 06 Nov 2021 19:02:03 +0800 |
In GNU Emacs 29.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.30, cairo
version 1.17.4)
of 2021-11-06 built on lilydjwg
Repository revision: 5a013838746c160cb296e0bc80a11795d2538f9a
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12013000
System Description: Arch Linux
It's originally reported at emacs-china.org [1].
emacs -Q, then open the following c++ snippet.
#+begin_src C++
#include <iostream>
#include <vector>
#define MAX 10000
void merge(std::vector<int> array, int p, int q, int r) {
int len_1 = q - p + 1;
int len_2 = r - q;
int a = 0;
int b = 0;
std::vector<int> left_array(len_1 + 2, 0);
std::vector<int> right_array(len_2 + 2, 0);
for (int i = 0; i < len_1; ++i) {
left_array[i] = array[p + i - 1];
}
for (int i = 0; i < len_2; ++i) {
right_array[i] = array[q + i];
}
left_array[len_1 + 1] = MAX;
right_array[len_2 + 1] = MAX;
for (int i = p; i < r + 1; ++i) {
if (left_array[a] <= right_array[b]) {
array[i] = left_array[a];
++a;
} else {
array[i] = right_array[b];
++b;
}
}
}
void merge_sort(std::vector<int> array, int p, int r) {
if (p < r) {
int q = (p + r) / 2;
merge_sort(array, p, q);
merge_sort(array, q + 1, r);
merge(array, p, q, r);
}
}
int main() {
std::vector<int> array = {3, 1, 2, 6, 4, 5};
merge_sort(array, 0, array.size() - 1);
for (auto i : array) {
std::cout << i << "\n";
}
return 0;
}
#+end_src
The profiler shows `jit-lock-function' costs 62% CPU time.
#+begin_src text
2952 62% - redisplay_internal (C function)
2936 62% - jit-lock-function
2936 62% - jit-lock-fontify-now
2920 62% - jit-lock--run-functions
2920 62% - run-hook-wrapped
2920 62% - #<compiled 0x19b62a583670403d>
2920 62% - font-lock-fontify-region
2920 62% - c-font-lock-fontify-region
2605 55% - font-lock-default-fontify-region
2534 53% - font-lock-fontify-keywords-region
1339 28% - c-font-lock-declarations
1317 27% - c-find-decl-spots
593 12% + #<compiled 0x62f8c10afa44432>
582 12% + c-bs-at-toplevel-p
#+end_src
[1]: https://emacs-china.org/t/emacs-c/18814
--
Zhiwei Chen
--- End Message ---
--- Begin Message ---
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Subject: |
Re: bug#51692: 29.0.50; High CPU in c++ mode. Type finder? |
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Date: |
Sat, 13 Nov 2021 12:10:07 +0000 |
Hello, Zhiwei, David, Yuri, and Lars.
On Sat, Nov 13, 2021 at 17:24:22 +0800, Zhiwei Chen wrote:
> Alan Mackenzie <acm@muc.de> writes:
> > Thanks! That's good to hear. I'll just give Zhiwei Chen a little time
> > to reply, and assuming (s)he doesn't find problems, I'll commit the fix.
> It solves the issue after applied the patch on Emacs trunk. Thanks.
Thanks to everybody for the testing. I have now committed the fix to
the master branch, and am closing the bug with this post.
> --
> Zhiwei Chen
--
Alan Mackenzie (Nuremberg, Germany).
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