247. Unit tests: Timer

This section describes the test plan for the timer library.

247.1. Description

  1. Stress tests.

    The objective of the timer stress tests is to check that there are no race conditions in list and status management. This test launches, resets and stops the timer very often on many cores at the same time.

    • Only one timer is used for this test.
    • On each core, the rte_timer_manage() function is called from the main loop every 3 microseconds.
    • In the main loop, the timer may be reset (randomly, with a probability of 0.5 %) 100 microseconds later on a random core, or stopped (with a probability of 0.5 % also).
    • In callback, the timer is can be reset (randomly, with a probability of 0.5 %) 100 microseconds later on the same core or on another core (same probability), or stopped (same probability).
  2. Basic test.

    This test performs basic functional checks of the timers. The test uses four different timers that are loaded and stopped under specific conditions in specific contexts.

    • Four timers are used for this test.
    • On each core, the rte_timer_manage() function is called from main loop every 3 microseconds.

    The autotest python script checks that the behavior is correct:

    • timer0
      • At initialization, timer0 is loaded by the master core, on master core in “single” mode (time = 1 second).
      • In the first 19 callbacks, timer0 is reloaded on the same core, then, it is explicitly stopped at the 20th call.
      • At t=25s, timer0 is reloaded once by timer2.
    • timer1
      • At initialization, timer1 is loaded by the master core, on the master core in “single” mode (time = 2 seconds).
      • In the first 9 callbacks, timer1 is reloaded on another core. After the 10th callback, timer1 is not reloaded anymore.
    • timer2
      • At initialization, timer2 is loaded by the master core, on the master core in “periodical” mode (time = 1 second).
      • In the callback, when t=25s, it stops timer3 and reloads timer0 on the current core.
    • timer3
      • At initialization, timer3 is loaded by the master core, on another core in “periodical” mode (time = 1 second).
      • It is stopped at t=25s by timer2.