Struct perf_event::Counts

pub struct Counts { /* fields omitted */ }

A collection of counts from a Group of counters.

This is the type returned by calling read on a Group. You can index it with a reference to a specific Counter:

let counts = group.read()?;
println!("cycles / instructions: {} / {} ({:.2} cpi)",
         counts[&cycles],
         counts[&insns],
         (counts[&cycles] as f64 / counts[&insns] as f64));

Or you can iterate over the results it contains:

for (id, value) in &counts {
    println!("Counter id {} has value {}", id, value);
}

The id values produced by this iteration are internal identifiers assigned by the kernel. You can use the Counter::id method to find a specific counter's id.

Methods

impl Counts

pub fn get(&self, member: &Counter) -> Option<&u64>

Return the value recorded for member in self, or None if member is not present.

If you know that member is in the group, you can simply index:

let cycles = counts[&cycle_counter];

Important traits for CountsIter<'c>

impl<'c> Iterator for CountsIter<'c> type Item = (u64, &'c u64);

pub fn iter(&self) -> CountsIter

Return an iterator over the counts in self.

for (id, value) in &counts {
    println!("Counter id {} has value {}", id, value);
}

Each item is a pair (id, &value), where id is the number assigned to the counter by the kernel (see Counter::id), and value is that counter's value.

Trait Implementations

impl Debug for Counts

fn fmt(&self, fmt: &mut Formatter) -> Result

Formats the value using the given formatter.

impl<'_> Index<&'_ Counter> for Counts

type Output = u64

The returned type after indexing.

fn index(&self, index: &Counter) -> &u64

Performs the indexing (container[index]) operation.

impl<'c> IntoIterator for &'c Counts

type Item = (u64, &'c u64)

The type of the elements being iterated over.

type IntoIter = CountsIter<'c>

Which kind of iterator are we turning this into?

Important traits for CountsIter<'c>

impl<'c> Iterator for CountsIter<'c> type Item = (u64, &'c u64);

fn into_iter(self) -> CountsIter<'c>

Creates an iterator from a value.