Created
January 9, 2018 03:22
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#![feature(test)] | |
#![feature(integer_atomics)] | |
extern crate test; | |
extern crate libc; | |
use std::f64; | |
use std::sync::atomic::{AtomicU64 as StdAtomicU64, Ordering}; | |
pub struct AtomicF64 { | |
inner: StdAtomicU64, | |
} | |
impl AtomicF64 { | |
pub fn new(val: f64) -> AtomicF64 { | |
AtomicF64 { | |
inner: StdAtomicU64::new(f64_to_u64(val)), | |
} | |
} | |
#[inline] | |
pub fn get(&self) -> f64 { | |
u64_to_f64(self.inner.load(Ordering::Relaxed)) | |
} | |
#[inline] | |
pub fn set(&self, val: f64) { | |
self.inner.store(f64_to_u64(val), Ordering::Relaxed) | |
} | |
#[inline] | |
pub fn inc_by(&self, delta: f64) { | |
loop { | |
let current = self.inner.load(Ordering::Acquire); | |
let new = u64_to_f64(current) + delta; | |
let swapped = self.inner | |
.compare_and_swap(current, f64_to_u64(new), Ordering::Release); | |
if swapped == current { | |
return; | |
} | |
} | |
} | |
} | |
fn u64_to_f64(val: u64) -> f64 { | |
f64::from_bits(val) | |
} | |
fn f64_to_u64(val: f64) -> u64 { | |
f64::to_bits(val) | |
} | |
pub struct AtomicU64 { | |
inner: StdAtomicU64, | |
} | |
impl AtomicU64 { | |
pub fn new(val: u64) -> AtomicU64 { | |
AtomicU64 { | |
inner: StdAtomicU64::new(val), | |
} | |
} | |
#[inline] | |
pub fn get(&self) -> u64 { | |
self.inner.load(Ordering::Acquire) | |
} | |
#[inline] | |
pub fn inc_by(&self, delta: u64) { | |
self.inner.fetch_add(delta, Ordering::Release); | |
} | |
} | |
fn get_cpuid() -> usize { | |
unsafe { | |
libc::sched_getcpu() as usize | |
} | |
} | |
#[cfg(test)] | |
mod tests { | |
use super::*; | |
use test::Bencher; | |
#[bench] | |
fn bench_getcpuid(b: &mut Bencher) { | |
b.iter(|| get_cpuid(); ); | |
} | |
#[bench] | |
fn bench_f64_inc(b: &mut Bencher) { | |
let v = AtomicF64::new(0.0); | |
b.iter(|| v.inc_by(1.0); ); | |
} | |
#[bench] | |
fn bench_u64_inc(b: &mut Bencher) { | |
let v = AtomicU64::new(0); | |
b.iter(|| v.inc_by(1); ); | |
} | |
#[bench] | |
fn bench_use_cpuid(b: &mut Bencher) { | |
let mut v = Vec::new(); | |
for _ in 0..1024 { | |
v.push(AtomicF64::new(1.0)); | |
} | |
b.iter(|| { | |
let i = get_cpuid(); | |
v[i].inc_by(1.0); | |
}); | |
} | |
#[bench] | |
fn bench_global(b: &mut Bencher) { | |
let v = AtomicF64::new(0.0); | |
b.iter(||{v.inc_by(1.0);}); | |
} | |
#[bench] | |
fn bench_local(b: &mut Bencher) { | |
let mut i = 0; | |
let v = AtomicF64::new(0.0); | |
let mut lv = 0.0; | |
b.iter(||{ | |
i += 1; | |
lv += 1.0; | |
if i == 100 { | |
i = 0; | |
v.inc_by(lv); | |
lv = 0.0; | |
} | |
}); | |
} | |
} |
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