rust/library/std/src/time, branch 1.58.0

Add #[must_use] to remaining std functions (O-Z)

2021-10-31T03:37:32+00:00

Rollup merge of #88651 - AGSaidi:monotonize-inner-64b-aarch64, r=dtolnay

2021-10-05T06:56:17+00:00

Use the 64b inner:monotonize() implementation not the 128b one for aarch64 aarch64 prior to v8.4 (FEAT_LSE2) doesn't have an instruction that guarantees untorn 128b reads except for completing a 128b load/store exclusive pair (ldxp/stxp) or compare-and-swap (casp) successfully. The requirement to complete a 128b read+write atomic is actually more expensive and more unfair than the previous implementation of monotonize() which used a Mutex on aarch64, especially at large core counts. For aarch64 switch to the 64b atomic implementation which is about 13x faster for a benchmark that involves many calls to Instant::now().

use AtomicU64::fetch_update instead of handrolled RMW-loop

2021-09-17T16:54:24+00:00

fix potential race in AtomicU64 time monotonizer

2021-09-16T16:32:28+00:00

Use the 64b inner:monotonize() implementation not the 128b one for aarch64

2021-09-04T20:11:26+00:00

aarch64 prior to v8.4 (FEAT_LSE2) doesn't have an instruction that guarantees untorn 128b reads except for completing a 128b load/store exclusive pair (ldxp/stxp) or compare-and-swap (casp) successfully. The requirement to complete a 128b read+write atomic is actually more expensive and more unfair than the previous implementation of monotonize() which used a Mutex on aarch64, especially at large core counts. For aarch64 switch to the 64b atomic implementation which is about 13x faster for a benchmark that involves many calls to Instant::now().

Fix typos “an”→“a” and a few different ones that appeared in the same search

2021-08-22T16:15:49+00:00

fix tests on wasm targets that have 32bit time_t and don't have threads

2021-08-20T18:34:23+00:00

[review] fix comment

2021-08-17T17:31:32+00:00

Co-authored-by: Amanieu d'Antras

correct overflows in the backslide case, add test

2021-08-16T20:15:52+00:00

Apply suggestions from code review

2021-08-15T22:01:41+00:00

Co-authored-by: Amanieu d'Antras