Enum Interval

pub enum Interval {
    Frequency(u64),
    Period(u64),
    PollPeriodMs(u32),
}

How often to snapshot the counter, along with any follower events and any additional sampled data such as callstacks.

This choice also controls how the readings are taken:

• With |frequency| or |period|, samples are taken by the kernel into a ring buffer. Analogous to perf record.
• With |poll_period_ms|, the userspace periodically snapshots the counters using the read syscall. Analogous to perf stat -I. Prefer the sampling options unless you’re recording PMUs whose perf drivers only support the reading mode.

If unset, an implementation-defined sampling default is used.

Variants

Frequency(u64)

Per-cpu sampling frequency in Hz, as requested from the kernel. Not the same as 1/period. Details: the actual sampling will still be based on a period, but the kernel will dynamically adjust it based on the observed event rate, to approximate this frequency. Works best with steady-rate events like timers. Not guaranteed to be honored as the kernel can throttle the sampling rate if it’s too high.

Period(u64)

Per-cpu sampling will occur every |period| counts of |event|. Prefer |frequency| by default, as it’s easier to oversample with a fixed period. Not guaranteed to be honored as the kernel can throttle the sampling rate if it’s too high.

PollPeriodMs(u32)

Per-cpu values are read by the userspace every interval. If using this mode, only follower events are supported. Options such as |PerfEventConfig.CallstackSampling| are incompatible. The period can’t be guaranteed to be exact since the readings are taken by userspace.

Implementations

impl Interval

pub fn encode<B>(&self, buf: &mut B)

where B: BufMut,

Encodes the message to a buffer.

pub fn merge<B>( field: &mut Option<Interval>, tag: u32, wire_type: WireType, buf: &mut B, ctx: DecodeContext, ) -> Result<(), DecodeError>

where B: Buf,

Decodes an instance of the message from a buffer, and merges it into self.

pub fn encoded_len(&self) -> usize

Returns the encoded length of the message without a length delimiter.

Trait Implementations

impl Clone for Interval

fn clone(&self) -> Interval

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Interval

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for Interval

fn eq(&self, other: &Interval) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Interval