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 5 use 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. 9 pub 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. start_profiling(&mut self, benchmark_id: &str, benchmark_dir: &Path)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. stop_profiling(&mut self, benchmark_id: &str, benchmark_dir: &Path)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. 24 pub struct ExternalProfiler; 25 impl Profiler for ExternalProfiler { start_profiling(&mut self, _benchmark_id: &str, _benchmark_dir: &Path)26 fn start_profiling(&mut self, _benchmark_id: &str, _benchmark_dir: &Path) {} stop_profiling(&mut self, _benchmark_id: &str, _benchmark_dir: &Path)27 fn stop_profiling(&mut self, _benchmark_id: &str, _benchmark_dir: &Path) {} 28 } 29