Run pid controller with grpc_millis

src/core/ext/transport/chttp2/transport/chttp2_transport.c

@@ -563,7 +563,8 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   }
 
   grpc_chttp2_act_on_flowctl_action(
-      exec_ctx, grpc_chttp2_flowctl_get_action(&t->flow_control, NULL), t,
+      exec_ctx,
+      grpc_chttp2_flowctl_get_action(exec_ctx, &t->flow_control, NULL), t,
       NULL);
 
   grpc_chttp2_initiate_write(exec_ctx, t,
@@ -1620,8 +1621,8 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
             &t->flow_control, &s->flow_control, GRPC_HEADER_SIZE_IN_BYTES,
             already_received);
         grpc_chttp2_act_on_flowctl_action(
-            exec_ctx,
-            grpc_chttp2_flowctl_get_action(&t->flow_control, &s->flow_control),
+            exec_ctx, grpc_chttp2_flowctl_get_action(exec_ctx, &t->flow_control,
+                                                     &s->flow_control),
             t, s);
       }
     }
@@ -2538,7 +2539,8 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
     grpc_endpoint_read(exec_ctx, t->ep, &t->read_buffer,
                        &t->read_action_locked);
     grpc_chttp2_act_on_flowctl_action(
-        exec_ctx, grpc_chttp2_flowctl_get_action(&t->flow_control, NULL), t,
+        exec_ctx,
+        grpc_chttp2_flowctl_get_action(exec_ctx, &t->flow_control, NULL), t,
         NULL);
     GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "keep_reading");
   } else {
@@ -2794,9 +2796,9 @@ static void incoming_byte_stream_next_locked(grpc_exec_ctx *exec_ctx,
                                            bs->next_action.max_size_hint,
                                            cur_length);
     grpc_chttp2_act_on_flowctl_action(
-        exec_ctx,
-        grpc_chttp2_flowctl_get_action(&t->flow_control, &s->flow_control), t,
-        s);
+        exec_ctx, grpc_chttp2_flowctl_get_action(exec_ctx, &t->flow_control,
+                                                 &s->flow_control),
+        t, s);
   }
   GPR_ASSERT(s->unprocessed_incoming_frames_buffer.length == 0);
   if (s->frame_storage.length > 0) {

src/core/ext/transport/chttp2/transport/flow_control.c

@@ -391,9 +391,10 @@ static grpc_chttp2_flowctl_urgency delta_is_significant(
 
 // Takes in a target and uses the pid controller to return a stabilized
 // guess at the new bdp.
-static double get_pid_controller_guess(grpc_chttp2_transport_flowctl* tfc,
+static double get_pid_controller_guess(grpc_exec_ctx* exec_ctx,
+                                       grpc_chttp2_transport_flowctl* tfc,
                                        double target) {
-  gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
+  grpc_millis now = grpc_exec_ctx_now(exec_ctx);
   if (!tfc->pid_controller_initialized) {
     tfc->last_pid_update = now;
     tfc->pid_controller_initialized = true;
@@ -409,11 +410,7 @@ static double get_pid_controller_guess(grpc_chttp2_transport_flowctl* tfc,
     return pow(2, target);
   }
   double bdp_error = target - grpc_pid_controller_last(&tfc->pid_controller);
-  gpr_timespec dt_timespec = gpr_time_sub(now, tfc->last_pid_update);
-  double dt = (double)dt_timespec.tv_sec + dt_timespec.tv_nsec * 1e-9;
-  if (dt > 0.1) {
-    dt = 0.1;
-  }
+  double dt = (double)(now - tfc->last_pid_update) * 1e-3;
   double log2_bdp_guess =
       grpc_pid_controller_update(&tfc->pid_controller, bdp_error, dt);
   tfc->last_pid_update = now;
@@ -441,7 +438,8 @@ static double get_target_under_memory_pressure(
 }
 
 grpc_chttp2_flowctl_action grpc_chttp2_flowctl_get_action(
-    grpc_chttp2_transport_flowctl* tfc, grpc_chttp2_stream_flowctl* sfc) {
+    grpc_exec_ctx* exec_ctx, grpc_chttp2_transport_flowctl* tfc,
+    grpc_chttp2_stream_flowctl* sfc) {
   grpc_chttp2_flowctl_action action;
   memset(&action, 0, sizeof(action));
   // TODO(ncteisen): tune this
@@ -473,7 +471,7 @@ grpc_chttp2_flowctl_action grpc_chttp2_flowctl_get_action(
 
       // run our target through the pid controller to stabilize change.
       // TODO(ncteisen): experiment with other controllers here.
-      double bdp_guess = get_pid_controller_guess(tfc, target);
+      double bdp_guess = get_pid_controller_guess(exec_ctx, tfc, target);
 
       // Though initial window 'could' drop to 0, we keep the floor at 128
       tfc->target_initial_window_size =

src/core/ext/transport/chttp2/transport/internal.h

@@ -269,7 +269,7 @@ typedef struct {
   /* pid controller */
   bool pid_controller_initialized;
   grpc_pid_controller pid_controller;
-  gpr_timespec last_pid_update;
+  grpc_millis last_pid_update;
 
   // pointer back to transport for tracing
   const grpc_chttp2_transport *t;
@@ -748,7 +748,8 @@ typedef struct {
 // Reads the flow control data and returns and actionable struct that will tell
 // chttp2 exactly what it needs to do
 grpc_chttp2_flowctl_action grpc_chttp2_flowctl_get_action(
-    grpc_chttp2_transport_flowctl *tfc, grpc_chttp2_stream_flowctl *sfc);
+    grpc_exec_ctx *exec_ctx, grpc_chttp2_transport_flowctl *tfc,
+    grpc_chttp2_stream_flowctl *sfc);
 
 // Takes in a flow control action and performs all the needed operations.
 void grpc_chttp2_act_on_flowctl_action(grpc_exec_ctx *exec_ctx,

src/core/ext/transport/chttp2/transport/parsing.c

@@ -359,8 +359,9 @@ static grpc_error *init_data_frame_parser(grpc_exec_ctx *exec_ctx,
                                       s == NULL ? NULL : &s->flow_control,
                                       t->incoming_frame_size);
   grpc_chttp2_act_on_flowctl_action(
-      exec_ctx, grpc_chttp2_flowctl_get_action(
-                    &t->flow_control, s == NULL ? NULL : &s->flow_control),
+      exec_ctx,
+      grpc_chttp2_flowctl_get_action(exec_ctx, &t->flow_control,
+                                     s == NULL ? NULL : &s->flow_control),
       t, s);
   if (err != GRPC_ERROR_NONE) {
     goto error_handler;