this-me 0.3.0

Rust ground for the modern .me semantic kernel.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152

use std::time::{Duration, Instant};

use this_me::kernel::{Kernel, Value};

const NODE_COUNT: usize = 4_000;
const UPDATES: usize = 2_000;
const WINDOW_SIZE: usize = 200;

#[derive(Debug)]
struct WindowRow {
    start: usize,
    end: usize,
    p50_ms: f64,
    p95_ms: f64,
    p99_ms: f64,
}

#[derive(Debug)]
struct OverallRow {
    p50_ms: f64,
    p95_ms: f64,
    p99_ms: f64,
    max_ms: f64,
}

fn main() {
    println!("Rust .me sustained mutation benchmark");
    println!("nodes={NODE_COUNT}, updates={UPDATES}, window={WINDOW_SIZE}\n");

    let result = run_sustained_mutation();

    println!("Summary:");
    println!("p50_ms\tp95_ms\tp99_ms\tmax_ms");
    println!(
        "{:.6}\t{:.6}\t{:.6}\t{:.6}",
        result.overall.p50_ms, result.overall.p95_ms, result.overall.p99_ms, result.overall.max_ms
    );

    println!("\nWindowed p95 drift check:");
    println!("window\tp50_ms\tp95_ms\tp99_ms");
    for window in &result.windows {
        println!(
            "{}-{}\t{:.6}\t{:.6}\t{:.6}",
            window.start, window.end, window.p50_ms, window.p95_ms, window.p99_ms
        );
    }

    let first = result
        .windows
        .first()
        .map(|window| window.p95_ms)
        .unwrap_or_default();
    let last = result
        .windows
        .last()
        .map(|window| window.p95_ms)
        .unwrap_or_default();
    let drift = if first > 0.0 {
        (last - first) / first
    } else {
        0.0
    };
    println!("\np95 drift: {:.2}%", drift * 100.0);
}

struct SustainedResult {
    overall: OverallRow,
    windows: Vec<WindowRow>,
}

fn run_sustained_mutation() -> SustainedResult {
    let mut kernel = Kernel::new();

    for index in 1..=NODE_COUNT {
        kernel
            .postulate(format!("items[{index}].value"), 10 + (index % 7) as u64)
            .expect("item value write should succeed");
    }
    kernel
        .postulate("factor", 1_u64)
        .expect("factor write should succeed");
    kernel
        .derive("items[1]", "score", "value * 2")
        .expect("warm item derivation should succeed");
    kernel
        .derive(format!("items[{NODE_COUNT}]"), "score", "value * factor")
        .expect("measured item derivation should succeed");

    assert_eq!(
        kernel.read(format!("items[{NODE_COUNT}].score")),
        Some(&Value::from(base_value() as f64))
    );

    let mut samples = Vec::with_capacity(UPDATES);

    for update in 1..=UPDATES {
        let factor = (update % 17) + 1;
        let started = Instant::now();
        kernel
            .postulate("factor", factor as u64)
            .expect("factor mutation should succeed");
        let score = kernel
            .read(format!("items[{NODE_COUNT}].score"))
            .cloned()
            .expect("measured score should be readable");
        samples.push(started.elapsed());
        assert_eq!(score, Value::from((base_value() * factor as u64) as f64));
    }

    let mut sorted = samples.clone();
    sorted.sort_unstable();

    let windows = samples
        .chunks(WINDOW_SIZE)
        .enumerate()
        .map(|(index, window)| {
            let mut sorted_window = window.to_vec();
            sorted_window.sort_unstable();
            WindowRow {
                start: index * WINDOW_SIZE + 1,
                end: index * WINDOW_SIZE + window.len(),
                p50_ms: millis(percentile(&sorted_window, 50)),
                p95_ms: millis(percentile(&sorted_window, 95)),
                p99_ms: millis(percentile(&sorted_window, 99)),
            }
        })
        .collect::<Vec<_>>();

    SustainedResult {
        overall: OverallRow {
            p50_ms: millis(percentile(&sorted, 50)),
            p95_ms: millis(percentile(&sorted, 95)),
            p99_ms: millis(percentile(&sorted, 99)),
            max_ms: millis(*sorted.last().expect("samples should not be empty")),
        },
        windows,
    }
}

fn base_value() -> u64 {
    10 + (NODE_COUNT % 7) as u64
}

fn percentile(samples: &[Duration], percentile: usize) -> Duration {
    assert!(!samples.is_empty());
    let index = ((samples.len() - 1) * percentile).div_ceil(100);
    samples[index.min(samples.len() - 1)]
}

fn millis(duration: Duration) -> f64 {
    duration.as_secs_f64() * 1_000.0
}