OXYGENHUB
# 10b4fd430eab oxygen / crates / oxy-core / src / timing.rs
2.5 KiB · Rust · last changed A Git import commit costs what it changes 1 month ago source blame history raw
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//! Opt-in phase timings (`OXY_TIMINGS=1`): each named phase prints its
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//! duration to stderr, for measuring where a command spends its time
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//! without a profiler.
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use std::sync::OnceLock;
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use std::time::Instant;
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pub fn enabled() -> bool {
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    static ON: OnceLock<bool> = OnceLock::new();
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    *ON.get_or_init(|| std::env::var_os("OXY_TIMINGS").is_some_and(|v| !v.is_empty() && v != "0"))
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}
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/// Report a duration measured by hand (several intervals summed), if timings are on.
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pub fn record(name: &str, d: std::time::Duration) {
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    if enabled() {
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        eprintln!("timing {:<28} {:>9.2} ms", name, d.as_secs_f64() * 1000.0);
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    }
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}
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/// Prints `timing <name> <ms>` when dropped, if timings are on.
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pub struct Phase {
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    name: &'static str,
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    started: Option<Instant>,
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}
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/// Start timing a phase; the guard reports when it goes out of scope.
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pub fn phase(name: &'static str) -> Phase {
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    Phase {
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        name,
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        started: enabled().then(Instant::now),
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    }
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}
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impl Drop for Phase {
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    fn drop(&mut self) {
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        if let Some(t) = self.started {
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            eprintln!(
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                "timing {:<28} {:>9.2} ms",
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                self.name,
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                t.elapsed().as_secs_f64() * 1000.0
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            );
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        }
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    }
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}
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static TOTALS: std::sync::Mutex<Vec<(&'static str, std::time::Duration)>> =
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    std::sync::Mutex::new(Vec::new());
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/// Add `d` to the running total for `name`, for a phase repeated many
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/// times (once per imported commit, say); `report_totals` prints them.
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pub fn add(name: &'static str, d: std::time::Duration) {
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    if !enabled() {
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        return;
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    }
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    let mut t = TOTALS.lock().unwrap_or_else(|e| e.into_inner());
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    match t.iter_mut().find(|(n, _)| *n == name) {
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        Some((_, total)) => *total += d,
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        None => t.push((name, d)),
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    }
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}
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/// Print and clear the totals `add` gathered.
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pub fn report_totals() {
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    if !enabled() {
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        return;
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    }
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    let t = std::mem::take(&mut *TOTALS.lock().unwrap_or_else(|e| e.into_inner()));
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    for (name, d) in t {
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        record(name, d);
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    }
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}
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/// Times from one point to the next, adding each interval to a total.
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pub struct Laps(Option<Instant>);
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impl Laps {
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    pub fn start() -> Laps {
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        Laps(enabled().then(Instant::now))
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    }
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    /// Add the time since the last lap to `name`'s total.
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    pub fn lap(&mut self, name: &'static str) {
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        if let Some(t) = &mut self.0 {
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            let now = Instant::now();
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            add(name, now - *t);
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            *t = now;
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        }
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    }
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}