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
153
154
155
156
157
158
159
160
161
162
163
164
165
166

//! `Perf` measures the selected perf events using the perf interface of the Linux kernel.
//!
//! # Example
//!
//! ```rust
//! extern crate criterion_perf_events;
//! extern crate perfcnt;
//!
//! # fn fibonacci_slow(_: usize) {}
//! # fn fibonacci_fast(_: usize) {}
//!
//! use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion};
//! use criterion_perf_events::Perf;
//! use perfcnt::linux::HardwareEventType as Hardware;
//! use perfcnt::linux::PerfCounterBuilderLinux as Builder;
//!
//! fn bench(c: &mut Criterion<Perf>) {
//!     let mut group = c.benchmark_group("fibonacci");
//!
//!     for i in 0..20 {
//!         group.bench_function(BenchmarkId::new("slow", i), |b| b.iter(|| fibonacci_slow(i)));
//!         group.bench_function(BenchmarkId::new("fast", i), |b| b.iter(|| fibonacci_fast(i)));
//!     }
//!
//!     group.finish()
//! }
//!
//! criterion_group!(
//!     name = my_bench;
//!     config = Criterion::default().with_measurement(Perf::new(Builder::from_hardware_event(Hardware::CacheMisses)));
//!     targets = bench
//! );
//! criterion_main!(my_bench);
//! ```

extern crate perfcnt;

use criterion::{
    measurement::{Measurement, ValueFormatter},
    Throughput,
};
use std::cell::RefCell;

use perfcnt::linux::PerfCounter;
use perfcnt::linux::PerfCounterBuilderLinux;
use perfcnt::AbstractPerfCounter;

/// `perf` implements `criterion::measurement::Measurement` so it can be used in criterion to measure perf events.
/// Create a struct via `Perf::new()`.
pub struct Perf {
    counter: RefCell<PerfCounter>,
}

impl Perf {
    /// Creates a new criterion measurement plugin that measures perf events.
    ///
    /// # Argument
    ///
    /// * `builder` - A PerfCounterBuilderLinux from the crate perfcnt that is configured for the selected counter.
    ///
    /// # Remarks
    ///
    /// Should only fail if you select a counter that is not available on your system or you do not have the necessarry access rights.
    pub fn new(mut builder: PerfCounterBuilderLinux) -> Perf {
        Perf {
            counter: RefCell::new(
                builder
                    .for_pid(std::process::id() as i32)
                    .disable()
                    .finish()
                    .expect("Could not create counter"),
            ),
        }
    }
}

impl Measurement for Perf {
    type Intermediate = u64;
    type Value = u64;

    fn start(&self) -> Self::Intermediate {
        self.counter
            .borrow()
            .start()
            .expect("Could not read perf counter");
        0
    }

    fn end(&self, _i: Self::Intermediate) -> Self::Value {
        self.counter
            .borrow()
            .stop()
            .expect("Could not stop perf counter");
        let ret = self
            .counter
            .borrow_mut()
            .read()
            .expect("Could not read perf counter");
        self.counter
            .borrow_mut()
            .reset()
            .expect("Could not reset perf counter");
        ret
    }

    fn add(&self, v1: &Self::Value, v2: &Self::Value) -> Self::Value {
        v1 + v2
    }

    fn zero(&self) -> Self::Value {
        0
    }

    fn to_f64(&self, value: &Self::Value) -> f64 {
        *value as f64
    }

    fn formatter(&self) -> &dyn ValueFormatter {
        &PerfFormatter
    }
}

struct PerfFormatter;

impl ValueFormatter for PerfFormatter {
    fn format_value(&self, value: f64) -> String {
        format!("{:.4} cycles", value)
    }

    fn format_throughput(&self, throughput: &Throughput, value: f64) -> String {
        match throughput {
            Throughput::Bytes(b) => format!("{:.4} events/byte", value / *b as f64),
            Throughput::Elements(b) => format!("{:.4} events/element", value / *b as f64),
        }
    }

    fn scale_values(&self, _typical_value: f64, _values: &mut [f64]) -> &'static str {
        "events"
    }

    fn scale_throughputs(
        &self,
        _typical_value: f64,
        throughput: &Throughput,
        values: &mut [f64],
    ) -> &'static str {
        match throughput {
            Throughput::Bytes(n) => {
                for val in values {
                    *val /= *n as f64;
                }
                "events/byte"
            }
            Throughput::Elements(n) => {
                for val in values {
                    *val /= *n as f64;
                }
                "events/element"
            }
        }
    }

    fn scale_for_machines(&self, _values: &mut [f64]) -> &'static str {
        "events"
    }
}