47a59dda25
* Add `getrandom_uninit(dest: &mut [MaybeUninit<u8>]) -> ...`. Add a public API for filling an `&mut [MaybeUninit<u8>]`. This will primarily serve as the building block for more typeful APIs for constructing random arrays. Increase the MSRV to 1.36, as `MaybeUninit` was added in that release. Fixes #226. * Revert testing changes Signed-off-by: Joe Richey <joerichey@google.com> * Allow rdrand tests to work with new implementation Signed-off-by: Joe Richey <joerichey@google.com> * Add Additional benchmarks and buffer size Signed-off-by: Joe Richey <joerichey@google.com> * Use pointer casts instead of transmute Signed-off-by: Joe Richey <joerichey@google.com> * Avoid initializing the buffer in `getrandom_uninit` benchmarks. * Benchmarks: Consume the result in `black_box`. Signed-off-by: Joe Richey <joerichey@google.com> Co-authored-by: Joe Richey <joerichey@google.com>
65 lines
2.0 KiB
Rust
65 lines
2.0 KiB
Rust
#![feature(test)]
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#![feature(maybe_uninit_as_bytes)]
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extern crate test;
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use std::mem::MaybeUninit;
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// Used to benchmark the throughput of getrandom in an optimal scenario.
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// The buffer is hot, and does not require initialization.
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#[inline(always)]
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fn bench_getrandom<const N: usize>(b: &mut test::Bencher) {
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b.bytes = N as u64;
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b.iter(|| {
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let mut buf = [0u8; N];
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getrandom::getrandom(&mut buf[..]).unwrap();
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test::black_box(buf);
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});
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}
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// Used to benchmark the throughput of getrandom is a slightly less optimal
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// scenario. The buffer is still hot, but requires initialization.
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#[inline(always)]
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fn bench_getrandom_uninit<const N: usize>(b: &mut test::Bencher) {
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b.bytes = N as u64;
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b.iter(|| {
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let mut buf: MaybeUninit<[u8; N]> = MaybeUninit::uninit();
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let _ = getrandom::getrandom_uninit(buf.as_bytes_mut()).unwrap();
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let buf: [u8; N] = unsafe { buf.assume_init() };
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test::black_box(buf)
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});
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}
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macro_rules! bench {
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( $name:ident, $size:expr ) => {
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pub mod $name {
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#[bench]
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pub fn bench_getrandom(b: &mut test::Bencher) {
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super::bench_getrandom::<{ $size }>(b);
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}
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#[bench]
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pub fn bench_getrandom_uninit(b: &mut test::Bencher) {
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super::bench_getrandom_uninit::<{ $size }>(b);
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}
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}
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};
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}
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// 16 bytes (128 bits) is the size of an 128-bit AES key/nonce.
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bench!(aes128, 128 / 8);
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// 32 bytes (256 bits) is the seed sized used for rand::thread_rng
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// and the `random` value in a ClientHello/ServerHello for TLS.
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// This is also the size of a 256-bit AES/HMAC/P-256/Curve25519 key
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// and/or nonce.
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bench!(p256, 256 / 8);
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// A P-384/HMAC-384 key and/or nonce.
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bench!(p384, 384 / 8);
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// Initializing larger buffers is not the primary use case of this library, as
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// this should normally be done by a userspace CSPRNG. However, we have a test
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// here to see the effects of a lower (amortized) syscall overhead.
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bench!(page, 4096);
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