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use time;
use std::mem;
use core::*;
use core::Kind::*;
use std::sync::atomic::AtomicUsize;
use std::sync::atomic::Ordering::*;
use std::usize;
use self::ScoreType::*;
#[derive(Debug, Clone, Copy)]
pub enum ScoreType {
Count(u64),
Sum(u64),
Max(u64),
Min(u64),
Mean(f64),
Rate(f64),
}
pub type ScoreSnapshot = (Kind, String, Vec<ScoreType>);
#[derive(Debug)]
pub struct Scoreboard {
kind: Kind,
name: String,
scores: [AtomicUsize; 5],
}
impl Scoreboard {
pub fn new(kind: Kind, name: String) -> Self {
let now = time::precise_time_ns() as usize;
Scoreboard {
kind,
name,
scores: unsafe { mem::transmute(Scoreboard::blank(now)) },
}
}
#[inline]
fn blank(now: usize) -> [usize; 5] {
[now, 0, 0, usize::MIN, usize::MAX]
}
pub fn update(&self, value: Value) -> () {
let value = value as usize;
self.scores[1].fetch_add(1, Acquire);
match self.kind {
Marker => {}
_ => {
self.scores[2].fetch_add(value, Acquire);
swap_if_more(&self.scores[3], value);
swap_if_less(&self.scores[4], value);
}
}
}
fn snapshot(&self, now: usize, scores: &mut [usize; 5]) -> bool {
scores[0] = self.scores[0].swap(now, Release);
scores[1] = self.scores[1].swap(0, Release);
scores[2] = self.scores[2].swap(0, Release);
if scores[1] == 0 {
return false;
}
scores[3] = self.scores[3].swap(usize::MIN, Release);
scores[4] = self.scores[4].swap(usize::MAX, Release);
true
}
pub fn reset(&self) -> Option<ScoreSnapshot> {
let now = time::precise_time_ns() as usize;
let mut scores = Scoreboard::blank(now);
if self.snapshot(now, &mut scores) {
let duration_seconds = (now - scores[0]) as f64 / 1_000_000_000.0;
let mut snapshot = Vec::new();
match self.kind {
Marker => {
snapshot.push(Count(scores[1] as u64));
snapshot.push(Rate(scores[1] as f64 / duration_seconds))
}
Gauge => {
snapshot.push(Max(scores[3] as u64));
snapshot.push(Min(scores[4] as u64));
snapshot.push(Mean(scores[2] as f64 / scores[1] as f64));
}
Timer | Counter => {
snapshot.push(Count(scores[1] as u64));
snapshot.push(Sum(scores[2] as u64));
snapshot.push(Max(scores[3] as u64));
snapshot.push(Min(scores[4] as u64));
snapshot.push(Mean(scores[2] as f64 / scores[1] as f64));
snapshot.push(Rate(scores[2] as f64 / duration_seconds))
}
}
Some((self.kind, self.name.clone(), snapshot))
} else {
None
}
}
}
#[inline]
fn swap_if_more(counter: &AtomicUsize, new_value: usize) {
let mut current = counter.load(Acquire);
while current < new_value {
if counter.compare_and_swap(current, new_value, Release) == new_value {
break;
}
current = counter.load(Acquire);
}
}
#[inline]
fn swap_if_less(counter: &AtomicUsize, new_value: usize) {
let mut current = counter.load(Acquire);
while current > new_value {
if counter.compare_and_swap(current, new_value, Release) == new_value {
break;
}
current = counter.load(Acquire);
}
}
#[cfg(feature = "bench")]
mod bench {
use super::*;
use test;
#[bench]
fn bench_score_update_marker(b: &mut test::Bencher) {
let metric = Scoreboard::new(Marker, "event_a".to_string());
b.iter(|| test::black_box(metric.update(1)));
}
#[bench]
fn bench_score_update_count(b: &mut test::Bencher) {
let metric = Scoreboard::new(Counter, "event_a".to_string());
b.iter(|| test::black_box(metric.update(4)));
}
#[bench]
fn bench_score_snapshot(b: &mut test::Bencher) {
let metric = Scoreboard::new(Counter, "event_a".to_string());
let now = time::precise_time_ns() as usize;
let mut scores = Scoreboard::blank(now);
b.iter(|| test::black_box(metric.snapshot(now, &mut scores)));
}
}