[Octave-bug-tracker] [bug #55940] pause() takes too long if you call it a bunch

[Andrew Janke]

Follow-up Comment #23, bug #55940 (project octave):

Thanks!

Minor bug in delay.cpp:


   else if (option = 2)


That should be "option == 2", otherwise the else case (for direct call of
nanosleep) will never get hit.

I've added it to my test repo and modified the output so it only reports
too-long pauses, to make it easier to copy-and-paste output here. A simple "."
indicates a sleep that took less than 2x as long as requested.
https://github.com/apjanke/test-nanosleep-for-octave/blob/1fa1269bcdad7f4d88cdee1b0037b34f6be526ca/src-octfiles/delay.cpp

I've compiled it and run it under Octave 5.1.0. (Octave default is not
building for me right now.)

Results:


octave:1> delay
Using nanosleep (&delay_timespec, &rem);
....................................................................................................
octave:2> delay(1)
Using octave::sleep (0.200000, true)
Step    0: elapsed = 16.175480
Step    1: elapsed = 20.200037
Step    2: elapsed = 20.200055
Step    3: elapsed = 13.168963
[...]
octave:1> delay(2)
Using octave::sleep (0.200000, false)
....................................................................................................
octave:2>


Or:


octave:1> delay(1)
Using octave::sleep (0.200000, true)
....................................................................................................
octave:2> delay(1)
Using octave::sleep (0.200000, true)
..................................
Step   34: elapsed = 9.620640
Step   35: elapsed = 9.745313
Step   36: elapsed = 1.790912
Step   37: elapsed = 10.799203
Step   38: elapsed = 2.362160
Step   39: elapsed = 2.889009
Step   40: elapsed = 3.791923
Step   41: elapsed = 1.356964
Step   42: elapsed = 18.020698

Aborting because it's taking too darn long.

octave:3>


For a bit, I thought that the `octave::sleep (x, false)` case didn't cause
problems, but then I ran this:


octave:1> delay(2)
Using octave::sleep (0.200000, false)
....................................................................................................
octave:2> delay(2)
Using octave::sleep (0.200000, false)
......................................
Step   38: elapsed = 9.160260
Step   39: elapsed = 11.657525
Step   40: elapsed = 20.216943
Step   41: elapsed = 20.581857

Aborting because it's taking too darn long.

octave:3> delay(2)
Using octave::sleep (0.200000, false)
Step    0: elapsed = 14.097041
Step    1: elapsed = 12.041813
Step    2: elapsed = 8.248526
Step    3: elapsed = 19.842456
Step    4: elapsed = 17.350757

Aborting because it's taking too darn long.

octave:4>


The direct nanosleep call causes problems, too!


octave:1> delay
Using nanosleep (&delay_timespec, &rem);
....................................................................................................
octave:2> delay
Using nanosleep (&delay_timespec, &rem);
............................
Step   28: elapsed = 8.850037
Step   29: elapsed = 10.200040
Step   30: elapsed = 10.200059
Step   31: elapsed = 10.200043
Step   32: elapsed = 10.200044
Step   33: elapsed = 10.200041

Aborting because it's taking too darn long.

octave:3> delay
Using nanosleep (&delay_timespec, &rem);
Step    0: elapsed = 8.751405
Step    1: elapsed = 1.168990
Step    2: elapsed = 10.200013
.
Step    4: elapsed = 10.200064
Step    5: elapsed = 10.200065
Step    6: elapsed = 10.200068
Step    7: elapsed = 10.200046

Aborting because it's taking too darn long.

octave:4>


WTF?

So, to me, that doesn't sound like it's a problem in the pause() logic, but
something else.

    _______________________________________________________

Reply to this item at:

  <https://savannah.gnu.org/bugs/?55940>

_______________________________________________
  Message sent via Savannah
  https://savannah.gnu.org/