Use a small amount of unsafe code to optimise vec.remove & .insert #11061

huonw · 2013-12-19T03:00:30Z

Before:

test vec::bench::random_inserts                     ... bench:     15025 ns/iter (+/- 409)
test vec::bench::random_removes                     ... bench:     16063 ns/iter (+/- 276)

After:

test vec::bench::random_inserts                     ... bench:      5257 ns/iter (+/- 321)
test vec::bench::random_removes                     ... bench:      4980 ns/iter (+/- 94)

This makes the included benchmark more than 3 times faster. Also, `.unshift(x)` is now faster as `.insert(0, x)` which can reuse the allocation if necessary.

Also, add `.remove_opt` and replace `.unshift` with `.remove(0)`. The code size reduction seem to compensate for not having the optimised special cases. This makes the included benchmark more than 3 times faster.

Before: ``` test vec::bench::random_inserts ... bench: 15025 ns/iter (+/- 409) test vec::bench::random_removes ... bench: 16063 ns/iter (+/- 276) ``` After: ``` test vec::bench::random_inserts ... bench: 5257 ns/iter (+/- 321) test vec::bench::random_removes ... bench: 4980 ns/iter (+/- 94) ```

…llogiq `let_and_return`: lint 'static lifetimes, don't lint borrows in closures Fixes rust-lang#11056 Now also ignores functions returning `'static` lifetimes, since I noticed the `stdin.lock()` example was still being linted but doesn't need to be since rust-lang#93965 changelog: none

std::vec: replace .insert with a small amount of unsafe code.

8163251

This makes the included benchmark more than 3 times faster. Also, `.unshift(x)` is now faster as `.insert(0, x)` which can reuse the allocation if necessary.

std::vec: use some unsafe code to optimise remove.

acd2be4

Also, add `.remove_opt` and replace `.unshift` with `.remove(0)`. The code size reduction seem to compensate for not having the optimised special cases. This makes the included benchmark more than 3 times faster.

bors closed this Dec 19, 2013

bors merged commit acd2be4 into rust-lang:master Dec 19, 2013

huonw deleted the opt-unsafe-vec branch February 25, 2014 05:28

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Use a small amount of unsafe code to optimise vec.remove & .insert #11061

Use a small amount of unsafe code to optimise vec.remove & .insert #11061

huonw commented Dec 19, 2013

Use a small amount of unsafe code to optimise vec.remove & .insert #11061

Use a small amount of unsafe code to optimise vec.remove & .insert #11061

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huonw commented Dec 19, 2013