ruvector_profiler/
latency.rs

1#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
2pub struct LatencyRecord {
3    pub sample_id: usize,
4    pub wall_time_us: u64,
5    pub kernel_time_us: u64,
6    pub seq_len: usize,
7}
8
9#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
10pub struct LatencyStats {
11    pub p50_us: u64,
12    pub p95_us: u64,
13    pub p99_us: u64,
14    pub mean_us: f64,
15    pub std_us: f64,
16    pub n: usize,
17}
18
19/// Compute percentile and summary statistics from wall-time latencies.
20pub fn compute_latency_stats(records: &[LatencyRecord]) -> LatencyStats {
21    let n = records.len();
22    if n == 0 {
23        return LatencyStats { p50_us: 0, p95_us: 0, p99_us: 0, mean_us: 0.0, std_us: 0.0, n: 0 };
24    }
25    let mut times: Vec<u64> = records.iter().map(|r| r.wall_time_us).collect();
26    times.sort_unstable();
27    let mean = times.iter().sum::<u64>() as f64 / n as f64;
28    let var = times.iter().map(|&t| (t as f64 - mean).powi(2)).sum::<f64>() / n as f64;
29    LatencyStats {
30        p50_us: pctl(&times, 50.0), p95_us: pctl(&times, 95.0), p99_us: pctl(&times, 99.0),
31        mean_us: mean, std_us: var.sqrt(), n,
32    }
33}
34
35fn pctl(sorted: &[u64], p: f64) -> u64 {
36    let idx = ((p / 100.0 * sorted.len() as f64).ceil() as usize).min(sorted.len()).saturating_sub(1);
37    sorted[idx]
38}
39
40#[cfg(test)]
41mod tests {
42    use super::*;
43    fn recs(ts: &[u64]) -> Vec<LatencyRecord> {
44        ts.iter().enumerate().map(|(i, &t)| LatencyRecord {
45            sample_id: i, wall_time_us: t, kernel_time_us: t, seq_len: 128,
46        }).collect()
47    }
48
49    #[test] fn empty()  { assert_eq!(compute_latency_stats(&[]).n, 0); }
50    #[test] fn single() {
51        let s = compute_latency_stats(&recs(&[42]));
52        assert_eq!((s.p50_us, s.p99_us, s.n), (42, 42, 1));
53    }
54    #[test] fn multi() {
55        let s = compute_latency_stats(&recs(&[10,20,30,40,50,60,70,80,90,100]));
56        assert_eq!(s.p50_us, 50);
57        assert!((s.mean_us - 55.0).abs() < 1e-9);
58    }
59    #[test] fn unsorted() { assert_eq!(compute_latency_stats(&recs(&[100,10,50,90,20])).p50_us, 50); }
60}
ruvector_profiler/latency.rs

ruvector_profiler/
latency.rs
