Flags for testing BBR extensions

picoquic/bbr.c

@@ -25,6 +25,14 @@
 #include "cc_common.h"
 #include "picoquic_utils.h"
 
+#ifdef BBRExperiment
+#define BBRExpGate(ctx, test, action) { if (ctx->exp_flags.test) action; }
+#define BBRExpTest(ctx, test) ( (ctx)->exp_flags.test )
+#else
+#define BBRExpGate(ctx, test, action) {}
+#define BBRExpTest(ctx, test) (1)
+#endif
+
 #define RTTJitterBuffer On
 #define RTTJitterBufferStartup On
 #define RTTJitterBufferProbe On
@@ -257,6 +265,10 @@ typedef struct st_picoquic_bbr_state_t {
     /* Experimental extensions, may or maynot be a good idea. */
     uint64_t wifi_shadow_rtt; /* Shadow RTT used for wifi connections. */
     double quantum_ratio; /* allow application to use a different default than 0.1% of bandwidth (or 1ms of traffic) */
+#ifdef BBRExperiment
+    /* Control flags for BBR improvements */
+    bbr_exp exp_flags;
+#endif
 
 } picoquic_bbr_state_t;
 
@@ -439,6 +451,11 @@ static void BBROnInit(picoquic_bbr_state_t* bbr_state, picoquic_path_t* path_x,
     bbr_state->extra_acked_delivered = 0;
     /* Support for the wifi_shadow_rtt hack */
     bbr_state->wifi_shadow_rtt = path_x->cnx->quic->wifi_shadow_rtt;
+
+#ifdef BBRExperiment
+    /* Support for BBR Experiment */
+    bbr_state->exp_flags = path_x->cnx->quic->bbr_exp_flags;
+#endif
     /* Support for experimenting with the send_quantum ratio */
     bbr_state->quantum_ratio = path_x->cnx->quic->bbr_quantum_ratio;
     if (bbr_state->quantum_ratio == 0) {
@@ -675,7 +692,7 @@ static void BBROnExitRecovery(picoquic_bbr_state_t* bbr_state, picoquic_path_t*
         bbr_state->recovery_packet_number = UINT64_MAX;
         bbr_state->packet_conservation = 0;
 
-        if (bbr_state->is_pto_recovery) {
+        if (bbr_state->is_pto_recovery && BBRExpTest(bbr_state, do_handle_suspension)) {
             /* TODO:
              * we should try to enter startup with a high enough BW. However, 
              * simple attempts to restore the BW parameters have proven ineffective.
@@ -1639,7 +1656,7 @@ static int BBRCheckTimeToProbeBW(picoquic_bbr_state_t* bbr_state, picoquic_path_
 {
     if (BBRHasElapsedInPhase(bbr_state, bbr_state->bw_probe_wait, current_time) ||
         BBRIsRenoCoexistenceProbeTime(bbr_state, path_x) ||
-        BBRCheckAppLimitedEnded(bbr_state, rs)) {
+        (BBRExpTest(bbr_state, do_enter_probeBW_after_limited) && BBRCheckAppLimitedEnded(bbr_state, rs))) {
         BBRStartProbeBW_REFILL(bbr_state, path_x);
         return 1;
     }
@@ -1654,7 +1671,7 @@ static void BBRStartProbeBW_DOWN(picoquic_bbr_state_t* bbr_state, picoquic_path_
     bbr_state->cwnd_gain = BBRProbeBwDownCwndGain;   /* maintain cwnd */
     BBRResetCongestionSignals(bbr_state);
     bbr_state->bw_probe_up_cnt = UINT32_MAX; /* not growing inflight_hi */
-    if (bbr_state->probe_probe_bw_quickly) {
+    if (bbr_state->probe_probe_bw_quickly && BBRExpTest(bbr_state, do_rapid_start)) {
         BBRPickProbeWaitEarly(bbr_state);
     }
     else {
@@ -1762,7 +1779,7 @@ static void BBRUpdateProbeBWCyclePhase(picoquic_bbr_state_t* bbr_state, picoquic
 
     case picoquic_bbr_alg_probe_bw_up:
         if (BBRHasElapsedInPhase(bbr_state, bbr_state->min_rtt, current_time) &&
-            (bbr_state->nb_rtt_excess > 0 ||
+            ((BBRExpTest(bbr_state, do_exit_probeBW_up_on_delay) && bbr_state->nb_rtt_excess > 0) ||
             path_x->bytes_in_transit > BBRInflightWithBw(bbr_state, path_x, 1.25, bbr_state->max_bw))) {
             BBRStartProbeBW_DOWN(bbr_state, path_x, current_time);
         }
@@ -1902,7 +1919,7 @@ static void BBRCheckStartupDone(picoquic_bbr_state_t* bbr_state,
         BBRCheckStartupFullBandwidth(bbr_state, rs);
         BBRCheckStartupHighLoss(bbr_state, path_x, rs);
 #ifdef RTTJitterBufferStartup
-        if (IsRTTTooHigh(bbr_state)) {
+        if (IsRTTTooHigh(bbr_state) && BBRExpTest(bbr_state, do_early_exit)) {
             bbr_state->filled_pipe = 1;
         }
 #endif
@@ -2287,6 +2304,7 @@ static void picoquic_bbr_notify(
             break;
         case picoquic_congestion_notification_lost_feedback:
             /* Feedback has been lost. It will be restored at the next notification. */
+            BBRExpGate(bbr_state, do_control_lost, break);
             BBREnterLostFeedback(bbr_state, path_x);
             break;
         case picoquic_congestion_notification_rtt_measurement:

picoquic/picoquic.h

@@ -1528,6 +1528,24 @@ void picoquic_set_default_wifi_shadow_rtt(picoquic_quic_t* quic, uint64_t wifi_s
 */
 void picoquic_set_default_bbr_quantum_ratio(picoquic_quic_t* quic, double quantum_ratio);
 
+/* Temporary code, do define a set of BBR flags that
+* turn on and off individual extensions. We want to use that
+* to do "before/after" measurements.
+ */
+#define BBRExperiment on
+#ifdef BBRExperiment
+/* Control flags for BBR improvements */
+typedef struct st_bbr_exp {
+    unsigned int do_early_exit : 1;
+    unsigned int do_rapid_start : 1;
+    unsigned int do_handle_suspension : 1;
+    unsigned int do_control_lost : 1;
+    unsigned int do_exit_probeBW_up_on_delay : 1;
+    unsigned int do_enter_probeBW_after_limited : 1;
+} bbr_exp;
+
+void picoquic_set_bbr_exp(picoquic_quic_t * quic, bbr_exp* exp);
+#endif
 /* The experimental API 'picoquic_set_priority_limit_for_bypass' 
 * instruct the stack to send the high priority streams or datagrams
 * immediately, even if congestion control would normally prevent it.

picoquic/picoquic_internal.h

@@ -732,6 +732,11 @@ typedef struct st_picoquic_quic_t {
     struct st_picoquic_unified_logging_t* qlog_fns;
     picoquic_performance_log_fn perflog_fn;
     void* v_perflog_ctx;
+
+#ifdef BBRExperiment
+    bbr_exp bbr_exp_flags;
+#endif
+
 } picoquic_quic_t;
 
 picoquic_packet_context_enum picoquic_context_from_epoch(int epoch);

picoquic/quicctx.c

@@ -736,7 +736,17 @@ picoquic_quic_t* picoquic_create(uint32_t max_nb_connections,
                 }
             }
         }
-
+#ifdef BBRExperiment
+        if (ret == 0) {
+            quic->bbr_exp_flags.do_early_exit = 1;
+            quic->bbr_exp_flags.do_rapid_start = 1;
+            quic->bbr_exp_flags.do_handle_suspension = 1;
+            quic->bbr_exp_flags.do_control_lost = 1;
+            quic->bbr_exp_flags.do_exit_probeBW_up_on_delay = 1;
+            quic->bbr_exp_flags.do_enter_probeBW_after_limited = 1;
+        }
+#endif
+
         if (ret != 0) {
             picoquic_free(quic);
             quic = NULL;
@@ -4878,6 +4888,12 @@ void picoquic_set_default_bbr_quantum_ratio(picoquic_quic_t* quic, double quantu
     quic->bbr_quantum_ratio = quantum_ratio;
 }
 
+#ifdef BBRExperiment
+void picoquic_set_bbr_exp(picoquic_quic_t* quic, bbr_exp* exp)
+{
+    quic->bbr_exp_flags = *exp;
+}
+#endif
 void picoquic_set_priority_limit_for_bypass(picoquic_cnx_t* cnx, uint8_t priority_limit)
 {
     cnx->priority_limit_for_bypass = priority_limit;