From b4eae244826a0fb8907ef50c8ef9a38da40b719d Mon Sep 17 00:00:00 2001 From: Dennis Kobert Date: Sat, 8 Mar 2025 21:06:20 +0100 Subject: Vendor perf event --- perf-event/README.md | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 perf-event/README.md (limited to 'perf-event/README.md') diff --git a/perf-event/README.md b/perf-event/README.md new file mode 100644 index 0000000..b6754cd --- /dev/null +++ b/perf-event/README.md @@ -0,0 +1,50 @@ +## perf-event: a Rust interface to Linux performance monitoring + +This uses the Linux [`perf_event_open`][man] API to access performance monitoring +hardware and software. Use `Builder` to create a perf event counter, then use +`enable` and `disable` to start and stop counting. Call `read` to get your +count. + +For example, this counts the number of cycles used by the call to `println!`. +Try adjusting the length of the vector to see the cycle count change. + + use perf_event::Builder; + + fn main() -> std::io::Result<()> { + let mut counter = Builder::new().build()?; + + let vec = (0..=51).collect::>(); + + counter.enable()?; + println!("{:?}", vec); + counter.disable()?; + + println!("{} instructions retired", counter.read()?); + + Ok(()) + } + +Since we don't specify what sort of event we want to count, `Builder` defaults +to `PERF_COUNT_HW_INSTRUCTIONS` events, whose documentation says: + +> Retired instructions. Be careful, these can be affected by various issues, +> most notably hardware interrupt counts. + +The `examples` directory includes programs that count other sorts of events. + +[man]: http://man7.org/linux/man-pages/man2/perf_event_open.2.html + +## See also + +The [`perfcnt`] crate provides more extensive coverage of the Linux +`perf_event_open` API than this crate. + +Markus Stange's [`linux-perf-event-reader`][lper] supports events. +This crate only handles counters for now. + +The [`not-perf`] project is a rewrite of `perf` in Rust, and has a +bunch of code for dealing with the Linux perf API. + +[`perfcnt`]: https://crates.io/crates/perfcnt +[lper]: https://crates.io/crates/linux-perf-event-reader +[`not-perf`]: https://github.com/koute/not-perf -- cgit v1.3.1