Function pit_interrupt_notify

kernel/src/time.rs:36–53

This function is called by the timer interrupt handler

()

/// This function is called by the timer interrupt handler
pub fn pit_interrupt_notify() { 
    // Increment the number of PIT ticks
    PIT_TICKS.fetch_add(PIT_TICKS_PER_INTERRUPT, Ordering::Relaxed);

    // Get the change in TSC from last time, and update moving average of
    // TSC ticks per PIT tick.
    let new_tsc = time_stamp_counter();
    let last_tsc = LAST_TSC.swap(new_tsc, Ordering::Relaxed);
    let new_tsc_per_pit = (new_tsc - last_tsc) / PIT_TICKS_PER_INTERRUPT;
    let ma_tsc_per_pit = (new_tsc_per_pit + TSC_PER_PIT.load(Ordering::Relaxed)) / 2;
    TSC_PER_PIT.store(ma_tsc_per_pit, Ordering::Relaxed);

    // Store in user-accessible KernelInfo page
    let info = memory::kernel_info::get_mut();
    info.pit_ticks = PIT_TICKS.load(Ordering::Relaxed);
    info.last_tsc = new_tsc;
    info.tsc_per_pit = ma_tsc_per_pit;
}

/// Monotonic count of he number of microseconds since restart
///