On Sun, 2023-02-05 at 11:45 +0100, Roman Haefeli wrote:
And now - this sounds a bit crazy - while testing the scheduling_fix build, the official releases (0.53-1, 0.52-2, etc.) didn't exhibit the high CPU usage anymore. Later, after some more testing, it happened again though, but not with the scheduling_fix build. It's really difficult to determine exactly what circumstances lead to the high CPU usage. It's as if it's possible to "taint" CoreAudio and the scheduling_fix somehow "untaints" it.
After some more testing, the more likely reason for same Pd version showing different behavior is found in the saved preferences. The issue is much more likely triggered, when enabled callbacks are saved in the preferences and thus Pd enables callbacks at loading time. Toggling DSP then will almost certainly trigger high CPU usage.
Sorry for the confused reporting. Things are not trivial.
Roman