OXYGENHUB
# 19527875ebdc oxygen / crates / oxy-core / src / timing.rs
2.5 KiB · Rust · last changed Memory per phase with a counting allocator 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. With the counting allocator installed (the `oxy`
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//! binary's `alloc-stats` feature), each also prints live and peak memory
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//! and what the phase allocated.
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use std::sync::OnceLock;
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use std::time::Instant;
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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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    /// Allocator counters at the start, when counting.
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    mem: Option<crate::alloc_stats::Stats>,
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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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    let on = enabled();
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    Phase {
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        name,
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        started: on.then(Instant::now),
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        mem: if on {
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            crate::alloc_stats::stats()
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        } else {
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            None
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        },
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    }
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}
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fn mib(n: usize) -> f64 {
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    n as f64 / (1024.0 * 1024.0)
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}
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/// The allocator's counters as one line, when counting: for the end of a
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/// command.
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pub fn memory_summary() {
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    if let (true, Some(s)) = (enabled(), crate::alloc_stats::stats()) {
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        eprintln!(
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            "memory peak {:.1} MiB, live {:.1} MiB, {:.1} MiB in {} allocations",
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            mib(s.peak),
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            mib(s.live),
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            mib(s.total),
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            s.count
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        );
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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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            let ms = t.elapsed().as_secs_f64() * 1000.0;
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            match (self.mem, crate::alloc_stats::stats()) {
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                (Some(a), Some(b)) => eprintln!(
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                    "timing {:<28} {:>9.2} ms  live {:>8.1} MiB  peak {:>8.1} MiB  +{:.1} MiB in {} allocs",
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                    self.name,
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                    ms,
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                    mib(b.live),
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                    mib(b.peak),
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                    mib(b.total - a.total),
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                    b.count - a.count
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                ),
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                _ => eprintln!("timing {:<28} {:>9.2} ms", self.name, ms),
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            }
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        }
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    }
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}