qk_cache/
profile.rs

1//! Opt-in elapsed timings for cache operations, written to stderr.
2
3use std::sync::OnceLock;
4use std::time::Instant;
5
6static ENABLED: OnceLock<bool> = OnceLock::new();
7
8/// Enable timings for this process before its first cache operation.
9/// `QK_PROFILE_CACHE=1` also enables them when no caller configures profiling.
10pub fn enable() {
11    let _ = ENABLED.set(true);
12}
13
14pub(crate) struct Span<'a> {
15    task: &'a str,
16    stage: &'static str,
17    started: Option<Instant>,
18    counts: Vec<(&'static str, String)>,
19}
20
21pub(crate) fn span<'a>(task: &'a str, stage: &'static str) -> Span<'a> {
22    let enabled = *ENABLED
23        .get_or_init(|| std::env::var_os("QK_PROFILE_CACHE").is_some_and(|value| value == "1"));
24    Span {
25        task,
26        stage,
27        started: enabled.then(Instant::now),
28        counts: Vec::new(),
29    }
30}
31
32impl Span<'_> {
33    /// Adds a count to the span's line, such as the bytes it received.
34    pub(crate) fn count(&mut self, name: &'static str, value: u64) {
35        if self.started.is_some() {
36            self.counts.push((name, value.to_string()));
37        }
38    }
39
40    /// Adds text to the span's line, such as how a server says it spent the
41    /// time; whitespace is left out, so the line still splits on spaces.
42    pub(crate) fn note(&mut self, name: &'static str, value: &str) {
43        if self.started.is_some() {
44            let value: String = value.chars().filter(|ch| !ch.is_whitespace()).collect();
45            self.counts.push((name, value));
46        }
47    }
48}
49
50impl Drop for Span<'_> {
51    fn drop(&mut self) {
52        if let Some(started) = self.started {
53            let mut line = format!(
54                "qk profile: task={} stage={} ms={:.3}",
55                self.task,
56                self.stage,
57                started.elapsed().as_secs_f64() * 1000.0
58            );
59            for (name, value) in &self.counts {
60                line.push_str(&format!(" {name}={value}"));
61            }
62            line.push('\n');
63            qk_executor::report::output(true, line.as_bytes());
64        }
65    }
66}
qk_cache/profile.rs

qk_cache/
profile.rs
