Enum linux_perf_event_reader::WakeupPolicy

pub enum WakeupPolicy {
    EventCount(u32),
    Watermark(u32),
}

Wakeup policy for “overflow notifications”. This controls the point at which the read call completes. (TODO: double check this)

There are two ways to generate overflow notifications.

The first is to set a WakeupPolicy that will trigger if a certain number of samples or bytes have been written to the mmap ring buffer.

The other way is by use of the PERF_EVENT_IOC_REFRESH ioctl. This ioctl adds to a counter that decrements each time the event overflows. When nonzero, POLLIN is indicated, but once the counter reaches 0 POLLHUP is indicated and the underlying event is disabled.

Variants

EventCount(u32)

Wake up every time N records of type RecordType::SAMPLE have been written to the mmap ring buffer.

Watermark(u32)

Wake up after N bytes of any record type have been written to the mmap ring buffer.

To receive a wakeup after every single record, choose Watermark(1). Watermark(0) is treated the same as Watermark(1).

Trait Implementations

impl Clone for WakeupPolicy

fn clone(&self) -> WakeupPolicy

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for WakeupPolicy

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

Formats the value using the given formatter.

impl Copy for WakeupPolicy