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#![feature(test)]
#![warn(rust_2018_idioms)]
extern crate test;
use bytes::Buf;
use test::Bencher;
/// Dummy Buf implementation
struct TestBuf {
buf: &'static [u8],
readlens: &'static [usize],
init_pos: usize,
pos: usize,
readlen_pos: usize,
readlen: usize,
}
impl TestBuf {
fn new(buf: &'static [u8], readlens: &'static [usize], init_pos: usize) -> TestBuf {
let mut buf = TestBuf {
buf,
readlens,
init_pos,
pos: 0,
readlen_pos: 0,
readlen: 0,
};
buf.reset();
buf
}
fn reset(&mut self) {
self.pos = self.init_pos;
self.readlen_pos = 0;
self.next_readlen();
}
/// Compute the length of the next read :
/// - use the next value specified in readlens (capped by remaining) if any
/// - else the remaining
fn next_readlen(&mut self) {
self.readlen = self.buf.len() - self.pos;
if let Some(readlen) = self.readlens.get(self.readlen_pos) {
self.readlen = std::cmp::min(self.readlen, *readlen);
self.readlen_pos += 1;
}
}
}
impl Buf for TestBuf {
fn remaining(&self) -> usize {
self.buf.len() - self.pos
}
fn advance(&mut self, cnt: usize) {
self.pos += cnt;
assert!(self.pos <= self.buf.len());
self.next_readlen();
}
fn chunk(&self) -> &[u8] {
if self.readlen == 0 {
Default::default()
} else {
&self.buf[self.pos..self.pos + self.readlen]
}
}
}
/// Dummy Buf implementation
/// version with methods forced to not be inlined (to simulate costly calls)
struct TestBufC {
inner: TestBuf,
}
impl TestBufC {
fn new(buf: &'static [u8], readlens: &'static [usize], init_pos: usize) -> TestBufC {
TestBufC {
inner: TestBuf::new(buf, readlens, init_pos),
}
}
fn reset(&mut self) {
self.inner.reset()
}
}
impl Buf for TestBufC {
#[inline(never)]
fn remaining(&self) -> usize {
self.inner.remaining()
}
#[inline(never)]
fn advance(&mut self, cnt: usize) {
self.inner.advance(cnt)
}
#[inline(never)]
fn chunk(&self) -> &[u8] {
self.inner.chunk()
}
}
macro_rules! bench {
($fname:ident, testbuf $testbuf:ident $readlens:expr, $method:ident $(,$arg:expr)*) => (
#[bench]
fn $fname(b: &mut Bencher) {
let mut bufs = [
$testbuf::new(&[1u8; 8+0], $readlens, 0),
$testbuf::new(&[1u8; 8+1], $readlens, 1),
$testbuf::new(&[1u8; 8+2], $readlens, 2),
$testbuf::new(&[1u8; 8+3], $readlens, 3),
$testbuf::new(&[1u8; 8+4], $readlens, 4),
$testbuf::new(&[1u8; 8+5], $readlens, 5),
$testbuf::new(&[1u8; 8+6], $readlens, 6),
$testbuf::new(&[1u8; 8+7], $readlens, 7),
];
b.iter(|| {
for i in 0..8 {
bufs[i].reset();
let buf: &mut dyn Buf = &mut bufs[i]; // type erasure
test::black_box(buf.$method($($arg,)*));
}
})
}
);
($fname:ident, slice, $method:ident $(,$arg:expr)*) => (
#[bench]
fn $fname(b: &mut Bencher) {
// buf must be long enough for one read of 8 bytes starting at pos 7
let arr = [1u8; 8+7];
b.iter(|| {
for i in 0..8 {
let mut buf = &arr[i..];
let buf = &mut buf as &mut dyn Buf; // type erasure
test::black_box(buf.$method($($arg,)*));
}
})
}
);
($fname:ident, option) => (
#[bench]
fn $fname(b: &mut Bencher) {
let data = [1u8; 1];
b.iter(|| {
for _ in 0..8 {
let mut buf = Some(data);
let buf = &mut buf as &mut dyn Buf; // type erasure
test::black_box(buf.get_u8());
}
})
}
);
}
macro_rules! bench_group {
($method:ident $(,$arg:expr)*) => (
bench!(slice, slice, $method $(,$arg)*);
bench!(tbuf_1, testbuf TestBuf &[], $method $(,$arg)*);
bench!(tbuf_1_costly, testbuf TestBufC &[], $method $(,$arg)*);
bench!(tbuf_2, testbuf TestBuf &[1], $method $(,$arg)*);
bench!(tbuf_2_costly, testbuf TestBufC &[1], $method $(,$arg)*);
// bench!(tbuf_onebyone, testbuf TestBuf &[1,1,1,1,1,1,1,1], $method $(,$arg)*);
// bench!(tbuf_onebyone_costly, testbuf TestBufC &[1,1,1,1,1,1,1,1], $method $(,$arg)*);
);
}
mod get_u8 {
use super::*;
bench_group!(get_u8);
}
mod get_u16 {
use super::*;
bench_group!(get_u16);
}
mod get_u32 {
use super::*;
bench_group!(get_u32);
}
mod get_u64 {
use super::*;
bench_group!(get_u64);
}
mod get_f32 {
use super::*;
bench_group!(get_f32);
}
mod get_f64 {
use super::*;
bench_group!(get_f64);
}
mod get_uint24 {
use super::*;
bench_group!(get_uint, 3);
}