perf(escapeAllSwigTags): reducing GC overhead#5620
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How to testgit clone -b perf/mem https://github.com/D-Sketon/hexo.git
cd hexo
npm install
npm test |
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SukkaW
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I believe that the root cause of the issue is that string concatenation doesn't copy strings; instead, it points to the existing strings using pointers. This is good for performance, so we should retain this behavior.
On the other hand, the concatenated string holds the reference of the old string, preventing the old string from being released.
Instead of manually creating a StringBuilder, you can try replacing return output with return output.replace('#'.repeat(output.length + 1), '') to see if it reduces GC pressure.
See also: https://romgrk.com/posts/optimizing-javascript#8-use-strings-carefully
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I tested it briefly and it doesn't seem to make a difference |
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I might have figured out why there's a memory difference. Although Assuming each post has 5,000 characters and there are 4,000 posts,
On the other hand, using
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@SukkaW Using |
What does it do?
A large amount of string concatenation can result in numerous consString objects, which cannot be cleared during Scavenge. This leads to old generation expansion.
12x many-posts
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after PR
12x many-posts concurrency=20
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after PR
4x many-posts concurrency=20
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after PR
1x many-posts concurrency=20
before PR
after PR
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