Delay not working?

dpeana

This is a very straightforward code but I do not understand the result:

class TimeTest(EnvExperiment):
    def build(self):
        self.setattr_device("core")
    
    @kernel
    def run(self):
        self.core.reset()
    
        time1 = self.core.get_rtio_counter_mu()
        delay(1*s)
        time2 = self.core.get_rtio_counter_mu()
        print("True kernel time: ",self.core.mu_to_seconds((time2-time1)))

When I run this, I would expect the print statement to return something on the order of 1 second but rather, regardless of the value in delay(), it returns ~ 1 us. I tried putting timing it with time.time() in this way:

    class TimeTest(EnvExperiment):
       def build(self):
           self.setattr_device("core")

       def run(self):
           t = time.time()
           self.delay_experiment()
           print("Runtime: ",time.time() - t)

       @kernel
        def delay_experiment(self):
            time1 = self.core.get_rtio_counter_mu()
            delay(1*s)
            time2 = self.core.get_rtio_counter_mu()
            print("True kernel time: ",self.core.mu_to_seconds((time2-time1)))

and it returns the same ~ 1 us for the 'True kernel time' and ₁₃₈ ms for the 'Runtime'. Likewise, I would expect both values to be ~ 1 s.

Is this an error or perhaps I just do not understand the way the timeline works?

LTGiardino

The delay function just moves the time cursor by the amount specified.
The real time cost of calling delay should be quite small however.
This is what you are seeing in our print statements, not the difference in the time cursor.

Check the timing concepts section of the manual.
Also check the functions now_mu and wait_until_mu.