1//! This module provides an extension trait which allows in-process profilers
2//! to be hooked into the `--profile-time` argument at compile-time. Users of
3//! out-of-process profilers such as perf don't need to do anything special.
4
5use std::path::Path;
6
7/// Extension trait for external crates to implement which provides start/stop
8/// hooks when profiling (but not when benchmarking) functions.
9pub trait Profiler {
10 /// This function is called when Criterion.rs starts profiling a particular
11 /// benchmark. It provides the stringified benchmark ID and
12 /// a path to a directory where the profiler can store its data.
13 fn start_profiling(&mut self, benchmark_id: &str, benchmark_dir: &Path);
14
15 /// This function is called after Criterion.rs stops profiling a particular
16 /// benchmark. The benchmark ID and directory are the same as in the call
17 /// to `start`, provided for convenience.
18 fn stop_profiling(&mut self, benchmark_id: &str, benchmark_dir: &Path);
19}
20
21/// Dummy profiler implementation, representing cases where the profiler is
22/// an external process (eg. perftools, etc.) which do not require start/stop
23/// hooks. This implementation does nothing and is used as the default.
24pub struct ExternalProfiler;
25impl Profiler for ExternalProfiler {
26 fn start_profiling(&mut self, _benchmark_id: &str, _benchmark_dir: &Path) {}
27 fn stop_profiling(&mut self, _benchmark_id: &str, _benchmark_dir: &Path) {}
28}
29