espnow: Remove unecessary 25ms latency on send().

glenn20 · glenn20 · commit 74bb60ade415 · 2023-04-30T16:53:21.000+10:00
Reduce minimum time to wait for acks from sent packets from 25ms to 1ms.
diff --git a/ports/esp8266/modespnow.c b/ports/esp8266/modespnow.c
@@ -90,10 +90,9 @@ static const size_t MAX_PACKET_LEN = (
 // Default timeout (millisec) to wait for incoming ESPNow messages (5 minutes).
 #define DEFAULT_RECV_TIMEOUT_MS (5 * 60 * 1000)
 
-// Number of milliseconds to wait (mp_hal_wait_ms()) in each loop
-// while waiting for send or receive packet.
-// Needs to be >15ms to permit yield to other tasks.
-#define BUSY_WAIT_MS (25)
+// Number of milliseconds to wait for pending responses to sent packets.
+// This is a fallback which should never be reached.
+#define PENDING_RESPONSES_TIMEOUT_MS 100
 
 // The data structure for the espnow_singleton.
 typedef struct _esp_espnow_obj_t {
@@ -347,9 +346,11 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(espnow_recvinto_obj, 2, 3, espnow_rec
 // ie. self->tx_responses == self->tx_packets.
 // Return the number of responses where status != ESP_NOW_SEND_SUCCESS.
 static void _wait_for_pending_responses(esp_espnow_obj_t *self) {
-    for (int i = 0; i < 90 && self->tx_responses < self->tx_packets; i++) {
-        // Won't yield unless delay > portTICK_PERIOD_MS (10ms)
-        mp_hal_delay_ms(BUSY_WAIT_MS);
+    for (int i = 0; i < PENDING_RESPONSES_TIMEOUT_MS; i++) {
+        if (self->tx_responses >= self->tx_packets) {
+            return;
+        }
+        mp_hal_delay_ms(1);  // Allow other tasks to run
     }
     // Note: the loop timeout is just a fallback - in normal operation
     // we should never reach that timeout.
