rust/library/std
bors b17491c8f6 Auto merge of #110211 - joboet:queue_lock, r=Amanieu
Replace pthread `RwLock` with custom implementation

This is one of the last items in #93740. I'm doing `RwLock` first because it is more self-contained and has less tradeoffs to make. The motivation is explained in the documentation, but in short: the pthread rwlock is slow and buggy and `std` can do much better. I considered implementing a parking lot, as was discussed in the tracking issue, but settled for the queue-based version because writing self-balancing binary trees is not fun in Rust...

This is a rather complex change, so I have added quite a bit of documentation to help explain it. Please point out any part that could be explained better.

~~The read performance is really good, I'm getting 4x the throughput of the pthread version and about the same performance as usync/parking_lot on an Apple M1 Max in the usync benchmark suite, but the write performance still falls way behind what usync and parking_lot achieve. I tried using a separate queue lock like what usync uses, but that didn't help. I'll try to investigate further in the future, but I wanted to get some eyes on this first.~~ [Resolved](https://github.com/rust-lang/rust/pull/110211#issuecomment-1513682336)

r? `@m-ou-se`
CC `@kprotty`
2024-02-12 09:45:22 +00:00
..
benches
src Auto merge of #110211 - joboet:queue_lock, r=Amanieu 2024-02-12 09:45:22 +00:00
tests Update feature names for new stdarch 2024-01-30 03:33:12 +00:00
build.rs Add support for custom JSON targets when using build-std. 2024-02-05 10:20:42 +00:00
Cargo.toml Update libc to 0.2.153 2024-02-01 23:58:42 -03:00