Revert "Improved transmission in high traffic (ARMmbed#2511)" (ARMmbed#2512)

This reverts commit 01749c2.

Author: Jarkko Paso

CHANGELOG.md

@@ -11,7 +11,6 @@
 * Added trace for mbed TLS errors
 * Optimized medium size network MPL parameters for 40 seconds multicast interval
 * Added traces to EAPOL TX failure
-* Improved handling of packet transmissions under heavy load
 * Added traces to Adaptation layer for Direct TX queue level decrease or increase by 20
 * New Network statitis info for Randon early detetction dropped packet at Adaptation layer.
 

source/MAC/IEEE802_15_4/mac_mcps_sap.c

@@ -2321,9 +2321,8 @@ static mac_pre_build_frame_t *mcps_sap_pd_req_queue_read(protocol_interface_rf_m
     // With FHSS, check TX conditions
     if (rf_mac_setup->fhss_api) {
         while (buffer) {
-            uint16_t frame_length = buffer->mac_payload_length + buffer->headerIeLength + buffer->payloadsIeLength;
             if (buffer->asynch_request || (flush == true) || (rf_mac_setup->fhss_api->check_tx_conditions(rf_mac_setup->fhss_api, !mac_is_ack_request_set(buffer),
-                                                                                                          buffer->msduHandle, mac_convert_frame_type_to_fhss(buffer->fcf_dsn.frametype), frame_length,
+                                                                                                          buffer->msduHandle, mac_convert_frame_type_to_fhss(buffer->fcf_dsn.frametype), buffer->mac_payload_length,
                                                                                                           rf_mac_setup->dev_driver->phy_driver->phy_header_length, rf_mac_setup->dev_driver->phy_driver->phy_tail_length) == true)) {
                 break;
             }

source/Service_Libs/fhss/fhss_ws.c

@@ -233,9 +233,6 @@ void fhss_set_txrx_slot_length(fhss_structure_t *fhss_structure)
 
 static uint32_t fhss_get_number_of_tx_slots(fhss_structure_t *fhss_structure)
 {
-    if (!fhss_structure->ws->txrx_slot_length_ms) {
-        return 0;
-    }
     return ((fhss_structure->ws->fhss_configuration.fhss_broadcast_interval - fhss_structure->ws->fhss_configuration.fhss_bc_dwell_interval) / fhss_structure->ws->txrx_slot_length_ms) / 2;
 }
 
@@ -367,40 +364,23 @@ static void fhss_broadcast_handler(const fhss_api_t *fhss_api, uint16_t delay)
         next_channel = fhss_structure->rx_channel;
         /* Start timer with random timeout to trigger unicast TX queue poll event.
          * For hops 0,1,4,5,8,9,...
-         * In high traffic:
-         * Min random is 1/1000 of the TX slot length.
-         * Max random is 1/100 of the TX slot length.
-         * Otherwise:
          * Min random is 1/100 of the TX slot length.
          * Max random is 1/5 of the TX slot length.
          *
          * For hops 2,3,6,7,10,11,...
-         * Min random is 1/1000 of the TX slot length plus 0.5*TX slot length.
-         * Max random is 1/100 of the TX slot length plus 0.5*TX slot length.
+         * Min random is 1/100 of the TX slot length plus 0.5*TX slot length.
+         * Max random is 1/10 of the TX slot length plus 0.5*TX slot length.
          * Event timer resolution is 50us.
          */
+        // returns 1 if polling of TX queue is done on latter half of the TX slot
+        uint8_t own_tx_trig_slot = calc_own_tx_trig_slot(fhss_structure->own_hop);
         uint32_t txrx_slot_length_us = MS_TO_US(fhss_structure->ws->txrx_slot_length_ms);
-        uint16_t queue_size = fhss_structure->callbacks.read_tx_queue_size(fhss_structure->fhss_api, false);
-        uint16_t uc_min_random, uc_max_random;
-        uint32_t tx_slot_shift_us = (txrx_slot_length_us) / 50;
-        uint32_t half_tx_slot_shift_us = tx_slot_shift_us / 2;
-        // For busy or latter half of the TX slot polling devices, use short random
-        if (queue_size >= QUEUE_SIZE_HIGH || calc_own_tx_trig_slot(fhss_structure->own_hop)) {
-            uc_min_random = ((txrx_slot_length_us / 1000) / 50);
-            uc_max_random = ((txrx_slot_length_us / 100) / 50);
-        } else {
-            uc_min_random = ((txrx_slot_length_us / 100) / 50);
-            uc_max_random = ((txrx_slot_length_us / 5) / 50);
-        }
-        // Shift for latter half of the TX slot
-        if (calc_own_tx_trig_slot(fhss_structure->own_hop)) {
-            uc_min_random += half_tx_slot_shift_us;
-            uc_max_random += half_tx_slot_shift_us;
-        }
-        // Shift for own TX slot
-        if (!fhss_ws_check_tx_allowed(fhss_structure)) {
-            uc_min_random += tx_slot_shift_us;
-            uc_max_random += tx_slot_shift_us;
+        uint16_t uc_min_random = (((txrx_slot_length_us / 2) * own_tx_trig_slot) / 50) + ((txrx_slot_length_us / 100) / 50);
+        uint16_t uc_max_random = (((txrx_slot_length_us / 2) * own_tx_trig_slot) / 50) + ((txrx_slot_length_us / 5) / 50);
+        bool tx_allowed = fhss_ws_check_tx_allowed(fhss_structure);
+        if (!tx_allowed) {
+            uc_min_random += (txrx_slot_length_us) / 50;
+            uc_max_random += (txrx_slot_length_us) / 50;
         }
         eventOS_callback_timer_start(fhss_structure->fhss_event_timer, randLIB_get_random_in_range(uc_min_random, uc_max_random));
 
@@ -730,28 +710,26 @@ static bool fhss_ws_check_tx_allowed(fhss_structure_t *fhss_structure)
 
 static bool fhss_ws_check_tx_time(fhss_structure_t *fhss_structure, uint16_t tx_length, uint8_t phy_header_length, uint8_t phy_tail_length)
 {
-    bool retval = true;
-    if (fhss_structure->own_hop != 0xff && fhss_structure->ws->fhss_configuration.fhss_broadcast_interval && fhss_structure->ws->fhss_configuration.fhss_bc_dwell_interval && fhss_get_number_of_tx_slots(fhss_structure)) {
-        uint32_t tx_time_ms = US_TO_MS(fhss_get_tx_time(fhss_structure, tx_length, phy_header_length, phy_tail_length));
-        // Check if there is enough time for transmitting before the next RX slot. Check only for devices which are polling TX queue in the beginning of TX slot.
-        if (!calc_own_tx_trig_slot(fhss_structure->own_hop)) {
-            uint32_t remaining_time_ms = get_remaining_slots_us(fhss_structure, fhss_broadcast_handler, MS_TO_US(fhss_structure->ws->fhss_configuration.fhss_broadcast_interval)) / 1000;
-            uint32_t tx_slot_begin_ms = (fhss_structure->ws->fhss_configuration.fhss_broadcast_interval - fhss_structure->ws->fhss_configuration.fhss_bc_dwell_interval) - (fhss_structure->ws->txrx_slot_length_ms * (fhss_structure->own_hop & 1));
-            tx_slot_begin_ms = tx_slot_begin_ms - (((tx_slot_begin_ms - remaining_time_ms) / (2 * fhss_structure->ws->txrx_slot_length_ms)) * (2 * fhss_structure->ws->txrx_slot_length_ms));
-            uint32_t rx_slot_begin_ms = tx_slot_begin_ms - fhss_structure->ws->txrx_slot_length_ms;
-            if ((remaining_time_ms < rx_slot_begin_ms) || ((remaining_time_ms - rx_slot_begin_ms) < tx_time_ms)) {
-                retval = false;
-            }
-        }
-        // Check if there is enough time for transmitting before the next multicast slot.
+    /*
+     * Check if there is enough time for transmitting before the next multicast slot.
+     */
 #ifdef FHSS_WS_PROTECT_MC_SLOTS
-        uint32_t time_to_bc_channel_ms = US_TO_MS(get_remaining_slots_us(fhss_structure, fhss_broadcast_handler, MS_TO_US(fhss_structure->ws->fhss_configuration.fhss_broadcast_interval)));
-        if (tx_time_ms > time_to_bc_channel_ms) {
-            retval = false;
-        }
-#endif
+    if (!fhss_structure->ws->fhss_configuration.fhss_broadcast_interval || !fhss_structure->ws->fhss_configuration.fhss_bc_dwell_interval) {
+        return true;
     }
-    return retval;
+    uint32_t tx_time = fhss_get_tx_time(fhss_structure, tx_length, phy_header_length, phy_tail_length);
+    uint32_t time_to_bc_channel_us = get_remaining_slots_us(fhss_structure, fhss_broadcast_handler, MS_TO_US(fhss_structure->ws->fhss_configuration.fhss_broadcast_interval));
+    if (tx_time > time_to_bc_channel_us) {
+        return false;
+    }
+    return true;
+#else
+    (void) fhss_structure;
+    (void) tx_length;
+    (void) phy_header_length;
+    (void) phy_tail_length;
+    return true;
+#endif
 }
 
 static bool fhss_ws_check_tx_conditions_callback(const fhss_api_t *api, bool is_broadcast_addr, uint8_t handle, int frame_type, uint16_t frame_length, uint8_t phy_header_length, uint8_t phy_tail_length)

source/Service_Libs/fhss/fhss_ws.h

@@ -18,17 +18,15 @@
 #define FHSS_WS_H_
 
 // TX slot length is optimised to this packet length
-#define OPTIMAL_PACKET_LENGTH   700
+#define OPTIMAL_PACKET_LENGTH   500
 // Default TX/RX slot length in milliseconds. Is used when datarate is not given by PHY.
-#define WS_TXRX_SLOT_LEN_MS             205
+#define WS_TXRX_SLOT_LEN_MS             100
 // Default minimum broadcast synchronization interval in seconds
 #define DEFAULT_MIN_SYNCH_INTERVAL      60
 // Drift compensation allowed if at least SYNCH_COMPENSATION_MIN_INTERVAL (seconds) since last synchronization
 #define SYNCH_COMPENSATION_MIN_INTERVAL 60
 // MAX compensation per received synchronization info in ns
 #define MAX_DRIFT_COMPENSATION_STEP     10
-// Goes to more rapid transmission mode when this limit is exceeded
-#define QUEUE_SIZE_HIGH 5
 typedef struct fhss_ws fhss_ws_t;
 
 struct fhss_ws {