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actix-web/actix-http/benches/content-length.rs

267 lines
8.2 KiB
Rust

use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion};
use bytes::BytesMut;
// benchmark sending all requests at the same time
fn bench_write_content_length(c: &mut Criterion) {
let mut group = c.benchmark_group("write_content_length");
let sizes = [
0, 1, 11, 83, 101, 653, 1001, 6323, 10001, 56329, 100001, 123456, 98724245,
4294967202,
];
for i in sizes.iter() {
group.bench_with_input(BenchmarkId::new("Original (unsafe)", i), i, |b, &i| {
b.iter(|| {
let mut b = BytesMut::with_capacity(35);
_original::write_content_length(i, &mut b)
})
});
group.bench_with_input(BenchmarkId::new("New (safe)", i), i, |b, &i| {
b.iter(|| {
let mut b = BytesMut::with_capacity(35);
_new::write_content_length(i, &mut b)
})
});
}
group.finish();
}
criterion_group!(benches, bench_write_content_length);
criterion_main!(benches);
mod _new {
use bytes::{BufMut, BytesMut};
const DIGITS_START: u8 = b'0';
/// NOTE: bytes object has to contain enough space
pub fn write_content_length(n: usize, bytes: &mut BytesMut) {
if n == 0 {
bytes.put_slice(b"\r\ncontent-length: 0\r\n");
return;
}
bytes.put_slice(b"\r\ncontent-length: ");
if n < 10 {
bytes.put_u8(DIGITS_START + (n as u8));
} else if n < 100 {
let n = n as u8;
let d10 = n / 10;
let d1 = n % 10;
bytes.put_u8(DIGITS_START + d10);
bytes.put_u8(DIGITS_START + d1);
} else if n < 1000 {
let n = n as u16;
let d100 = (n / 100) as u8;
let d10 = ((n / 10) % 10) as u8;
let d1 = (n % 10) as u8;
bytes.put_u8(DIGITS_START + d100);
bytes.put_u8(DIGITS_START + d10);
bytes.put_u8(DIGITS_START + d1);
} else if n < 10_000 {
let n = n as u16;
let d1000 = (n / 1000) as u8;
let d100 = ((n / 100) % 10) as u8;
let d10 = ((n / 10) % 10) as u8;
let d1 = (n % 10) as u8;
bytes.put_u8(DIGITS_START + d1000);
bytes.put_u8(DIGITS_START + d100);
bytes.put_u8(DIGITS_START + d10);
bytes.put_u8(DIGITS_START + d1);
} else if n < 100_000 {
let n = n as u32;
let d10000 = (n / 10000) as u8;
let d1000 = ((n / 1000) % 10) as u8;
let d100 = ((n / 100) % 10) as u8;
let d10 = ((n / 10) % 10) as u8;
let d1 = (n % 10) as u8;
bytes.put_u8(DIGITS_START + d10000);
bytes.put_u8(DIGITS_START + d1000);
bytes.put_u8(DIGITS_START + d100);
bytes.put_u8(DIGITS_START + d10);
bytes.put_u8(DIGITS_START + d1);
} else if n < 1_000_000 {
let n = n as u32;
let d100000 = (n / 100000) as u8;
let d10000 = ((n / 10000) % 10) as u8;
let d1000 = ((n / 1000) % 10) as u8;
let d100 = ((n / 100) % 10) as u8;
let d10 = ((n / 10) % 10) as u8;
let d1 = (n % 10) as u8;
bytes.put_u8(DIGITS_START + d100000);
bytes.put_u8(DIGITS_START + d10000);
bytes.put_u8(DIGITS_START + d1000);
bytes.put_u8(DIGITS_START + d100);
bytes.put_u8(DIGITS_START + d10);
bytes.put_u8(DIGITS_START + d1);
} else {
write_usize(n, bytes);
}
bytes.put_slice(b"\r\n");
}
fn write_usize(n: usize, bytes: &mut BytesMut) {
let mut n = n;
// 20 chars is max length of a usize (2^64)
// digits will be added to the buffer from lsd to msd
let mut buf = BytesMut::with_capacity(20);
while n > 9 {
// "pop" the least-significant digit
let lsd = (n % 10) as u8;
// remove the lsd from n
n = n / 10;
buf.put_u8(DIGITS_START + lsd);
}
// put msd to result buffer
bytes.put_u8(DIGITS_START + (n as u8));
// put, in reverse (msd to lsd), remaining digits to buffer
for i in (0..buf.len()).rev() {
bytes.put_u8(buf[i]);
}
}
}
mod _original {
use std::{mem, ptr, slice};
use bytes::{BufMut, BytesMut};
const DEC_DIGITS_LUT: &[u8] = b"0001020304050607080910111213141516171819\
2021222324252627282930313233343536373839\
4041424344454647484950515253545556575859\
6061626364656667686970717273747576777879\
8081828384858687888990919293949596979899";
/// NOTE: bytes object has to contain enough space
pub fn write_content_length(mut n: usize, bytes: &mut BytesMut) {
if n < 10 {
let mut buf: [u8; 21] = [
b'\r', b'\n', b'c', b'o', b'n', b't', b'e', b'n', b't', b'-', b'l',
b'e', b'n', b'g', b't', b'h', b':', b' ', b'0', b'\r', b'\n',
];
buf[18] = (n as u8) + b'0';
bytes.put_slice(&buf);
} else if n < 100 {
let mut buf: [u8; 22] = [
b'\r', b'\n', b'c', b'o', b'n', b't', b'e', b'n', b't', b'-', b'l',
b'e', b'n', b'g', b't', b'h', b':', b' ', b'0', b'0', b'\r', b'\n',
];
let d1 = n << 1;
unsafe {
ptr::copy_nonoverlapping(
DEC_DIGITS_LUT.as_ptr().add(d1),
buf.as_mut_ptr().offset(18),
2,
);
}
bytes.put_slice(&buf);
} else if n < 1000 {
let mut buf: [u8; 23] = [
b'\r', b'\n', b'c', b'o', b'n', b't', b'e', b'n', b't', b'-', b'l',
b'e', b'n', b'g', b't', b'h', b':', b' ', b'0', b'0', b'0', b'\r',
b'\n',
];
// decode 2 more chars, if > 2 chars
let d1 = (n % 100) << 1;
n /= 100;
unsafe {
ptr::copy_nonoverlapping(
DEC_DIGITS_LUT.as_ptr().add(d1),
buf.as_mut_ptr().offset(19),
2,
)
};
// decode last 1
buf[18] = (n as u8) + b'0';
bytes.put_slice(&buf);
} else {
bytes.put_slice(b"\r\ncontent-length: ");
convert_usize(n, bytes);
}
}
pub(crate) fn convert_usize(mut n: usize, bytes: &mut BytesMut) {
let mut curr: isize = 39;
let mut buf: [u8; 41] = unsafe { mem::MaybeUninit::uninit().assume_init() };
buf[39] = b'\r';
buf[40] = b'\n';
let buf_ptr = buf.as_mut_ptr();
let lut_ptr = DEC_DIGITS_LUT.as_ptr();
// eagerly decode 4 characters at a time
while n >= 10_000 {
let rem = (n % 10_000) as isize;
n /= 10_000;
let d1 = (rem / 100) << 1;
let d2 = (rem % 100) << 1;
curr -= 4;
unsafe {
ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
ptr::copy_nonoverlapping(
lut_ptr.offset(d2),
buf_ptr.offset(curr + 2),
2,
);
}
}
// if we reach here numbers are <= 9999, so at most 4 chars long
let mut n = n as isize; // possibly reduce 64bit math
// decode 2 more chars, if > 2 chars
if n >= 100 {
let d1 = (n % 100) << 1;
n /= 100;
curr -= 2;
unsafe {
ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
}
}
// decode last 1 or 2 chars
if n < 10 {
curr -= 1;
unsafe {
*buf_ptr.offset(curr) = (n as u8) + b'0';
}
} else {
let d1 = n << 1;
curr -= 2;
unsafe {
ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
}
}
unsafe {
bytes.extend_from_slice(slice::from_raw_parts(
buf_ptr.offset(curr),
41 - curr as usize,
));
}
}
}