seq: Directly write separator string, instead of using format#7562
Merged
sylvestre merged 1 commit intouutils:mainfrom Mar 24, 2025
Merged
seq: Directly write separator string, instead of using format#7562sylvestre merged 1 commit intouutils:mainfrom
sylvestre merged 1 commit intouutils:mainfrom
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Doing `stdout.write_all(separator.as_bytes())?` is quite a bit
faster than using format to do the same operation:
`write!(stdout, "{separator}")?`.
This speeds up by about 10% on simple cases.
We do the same for the terminator even though this has no measurable
performance impact.
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Author
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(probably a good idea to grep the rest of the repo for that pattern...) |
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GNU testsuite comparison: |
Contributor
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wahou, i wasn't expecting such difference |
drinkcat
commented
Mar 24, 2025
| @@ -260,15 +260,15 @@ fn print_seq( | |||
| let mut is_first_iteration = true; | |||
| while !done_printing(&value, &increment, &last) { | |||
| if !is_first_iteration { | |||
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Oh, I also tried to move that test out of the loop. That makes no difference.
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Doing
stdout.write_all(separator.as_bytes())?is quite a bit faster than using format to do the same operation:write!(stdout, "{separator}")?.This speeds up by about 10% on simple cases.
We do the same for the terminator even though this has no measurable performance impact.
Integer increments (no point comparing with coreutils on that one, it's much faster):
Float increments, we were already faster than coreutils, we gain another 10%: