diff options
| author | Angus Gratton <angus@redyak.com.au> | 2023-10-31 16:42:10 +1100 |
|---|---|---|
| committer | Damien George <damien@micropython.org> | 2023-11-03 18:26:51 +1100 |
| commit | 8c432ea2d437255eefb4aff18764936ad11b70c7 (patch) | |
| tree | 736d4bbf2ff2b8f0d86974bafa2a9044c7cb6d1e | |
| parent | b41055a5a3e1c51ee7ea274da4744dd47c211b3a (diff) | |
rp2: Remove 1ms timeout to make idle waiting tickless.
The main motivation for doing this was to reduce the latency when the
system is woken by a USB interrupt. The best_effort_wfe_or_timeout()
function calls into the pico-sdk dynamic timer framework which sets up a
new dynamic timer instance each time, and then has to tear it down before
continuing after a WFE.
Testing Python interrupt latency, it seems to be improved by about 12us
(from average of 46us to 34us running a Pin IRQ). C-based "scheduled
nodes" should see even lower latency.
This work was funded through GitHub Sponsors.
Signed-off-by: Angus Gratton <angus@redyak.com.au>
| -rw-r--r-- | ports/rp2/modmachine.c | 2 | ||||
| -rw-r--r-- | ports/rp2/mpconfigport.h | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/ports/rp2/modmachine.c b/ports/rp2/modmachine.c index 29a8dbed2..4c428cbdd 100644 --- a/ports/rp2/modmachine.c +++ b/ports/rp2/modmachine.c @@ -111,7 +111,7 @@ STATIC mp_obj_t machine_freq(size_t n_args, const mp_obj_t *args) { STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_freq_obj, 0, 1, machine_freq); STATIC mp_obj_t machine_idle(void) { - best_effort_wfe_or_timeout(make_timeout_time_ms(1)); + __wfe(); return mp_const_none; } STATIC MP_DEFINE_CONST_FUN_OBJ_0(machine_idle_obj, machine_idle); diff --git a/ports/rp2/mpconfigport.h b/ports/rp2/mpconfigport.h index 0a6331273..84a961db4 100644 --- a/ports/rp2/mpconfigport.h +++ b/ports/rp2/mpconfigport.h @@ -274,7 +274,7 @@ extern void mp_thread_end_atomic_section(uint32_t); #define MICROPY_EVENT_POLL_HOOK \ do { \ MICROPY_EVENT_POLL_HOOK_FAST; \ - best_effort_wfe_or_timeout(make_timeout_time_ms(1)); \ + __wfe(); \ } while (0); #define MICROPY_MAKE_POINTER_CALLABLE(p) ((void *)((mp_uint_t)(p) | 1)) |