[client] metrics: correlate Wayland presentation timing

client/displayservers/Wayland/presentation.c

@@ -30,11 +30,77 @@
 #include "common/debug.h"
 #include "common/time.h"
 
-struct FrameData
+struct WaylandPresentationFrame
 {
-  struct timespec sent;
+  atomic_uint                      refs;
+  struct wl_list                   link;
+  struct wp_presentation_feedback * feedback;
+  uint64_t                         frameToken;
+  struct timespec                  sent;
+  struct timespec                  swapReturn;
+  struct timespec                  presented;
+  bool                             swapDone;
+  bool                             swapValid;
+  bool                             feedbackDone;
+  bool                             feedbackValid;
+  bool                             timingComplete;
 };
 
+struct PresentationCompletion
+{
+  uint64_t frameToken;
+  uint64_t presentTime;
+  bool     notify;
+  bool     valid;
+};
+
+static void presentationFrameRelease(struct WaylandPresentationFrame * frame)
+{
+  if (atomic_fetch_sub_explicit(
+        &frame->refs, 1, memory_order_acq_rel) == 1)
+    free(frame);
+}
+
+static bool presentationOrdered(const struct timespec * left,
+    const struct timespec * right)
+{
+  return left->tv_sec > right->tv_sec ||
+    (left->tv_sec == right->tv_sec && left->tv_nsec >= right->tv_nsec);
+}
+
+static uint64_t presentationDelta(const struct timespec * left,
+    const struct timespec * right)
+{
+  struct timespec delta;
+  tsDiff(&delta, left, right);
+  return (uint64_t)delta.tv_sec * 1000000000ULL + delta.tv_nsec;
+}
+
+static void presentationCompleteLocked(
+    struct WaylandPresentationFrame * frame,
+    struct PresentationCompletion * completion)
+{
+  if (frame->timingComplete || !frame->swapDone || !frame->feedbackDone)
+    return;
+
+  frame->timingComplete   = true;
+  completion->notify      = frame->frameToken != 0;
+  completion->frameToken = frame->frameToken;
+  completion->valid      = frame->swapValid && frame->feedbackValid &&
+    presentationOrdered(&frame->presented, &frame->swapReturn);
+  if (completion->valid)
+    completion->presentTime = presentationDelta(
+        &frame->presented, &frame->swapReturn);
+}
+
+static void presentationNotify(
+    const struct PresentationCompletion * completion)
+{
+  if (completion->notify)
+    app_handleFramePresented(completion->frameToken,
+        completion->presentTime, completion->valid);
+}
+
 static void presentationClockId(void * data,
     struct wp_presentation * presentation, uint32_t clkId)
 {
@@ -57,18 +123,34 @@ static void presentationFeedbackPresented(void * opaque,
     struct wp_presentation_feedback * feedback, uint32_t tvSecHi, uint32_t tvSecLo,
     uint32_t tvNsec, uint32_t refresh, uint32_t seqHi, uint32_t seqLo, uint32_t flags)
 {
-  struct FrameData * data = opaque;
-  struct timespec present = {
+  struct WaylandPresentationFrame * frame = opaque;
+  const struct timespec present = {
     .tv_sec = (uint64_t) tvSecHi << 32 | tvSecLo,
     .tv_nsec = tvNsec,
   };
-  struct timespec delta;
+  struct PresentationCompletion completion = {};
 
-  tsDiff(&delta, &present, &data->sent);
-  ringbuffer_push(wlWm.photonTimings,
-      &(float){ delta.tv_sec * 1e3f + delta.tv_nsec * 1e-6f });
-  free(data);
+  if (tvNsec < 1000000000)
+  {
+    struct timespec delta;
+    tsDiff(&delta, &present, &frame->sent);
+    ringbuffer_push(wlWm.photonTimings,
+        &(float){ delta.tv_sec * 1e3f + delta.tv_nsec * 1e-6f });
+  }
+
+  INTERLOCKED_SECTION(wlWm.presentationLock,
+  {
+    wl_list_remove(&frame->link);
+    frame->feedback      = NULL;
+    frame->feedbackDone  = true;
+    frame->feedbackValid = tvNsec < 1000000000;
+    frame->presented     = present;
+    presentationCompleteLocked(frame, &completion);
+  });
+
+  presentationNotify(&completion);
   wp_presentation_feedback_destroy(feedback);
+  presentationFrameRelease(frame);
 }
 
 bool waylandGetFramePeriod(uint64_t * period)
@@ -82,8 +164,21 @@ bool waylandGetFramePeriod(uint64_t * period)
 static void presentationFeedbackDiscarded(void * data,
     struct wp_presentation_feedback * feedback)
 {
-  free(data);
+  struct WaylandPresentationFrame * frame = data;
+  struct PresentationCompletion completion = {};
+
+  INTERLOCKED_SECTION(wlWm.presentationLock,
+  {
+    wl_list_remove(&frame->link);
+    frame->feedback      = NULL;
+    frame->feedbackDone  = true;
+    frame->feedbackValid = false;
+    presentationCompleteLocked(frame, &completion);
+  });
+
+  presentationNotify(&completion);
   wp_presentation_feedback_destroy(feedback);
+  presentationFrameRelease(frame);
 }
 
 static const struct wp_presentation_feedback_listener presentationFeedbackListener = {
@@ -94,10 +189,13 @@ static const struct wp_presentation_feedback_listener presentationFeedbackListen
 
 bool waylandPresentationInit(void)
 {
+  LG_LOCK_INIT(wlWm.presentationLock);
+  wl_list_init(&wlWm.presentationFrames);
+  atomic_store_explicit(
+      &wlWm.presentationClockValid, false, memory_order_release);
+
   if (wlWm.presentation)
   {
-    atomic_store_explicit(
-        &wlWm.presentationClockValid, false, memory_order_release);
     wlWm.photonTimings = ringbuffer_new(256, sizeof(float));
     wlWm.photonGraph   = app_registerGraph("PHOTON", wlWm.photonTimings,
         0.0f, 30.0f, NULL);
@@ -109,36 +207,129 @@ bool waylandPresentationInit(void)
 
 void waylandPresentationFree(void)
 {
-  if (!wlWm.presentation)
-    return;
-
   atomic_store_explicit(
       &wlWm.presentationClockValid, false, memory_order_release);
-  wp_presentation_destroy(wlWm.presentation);
-  app_unregisterGraph(wlWm.photonGraph);
-  ringbuffer_free(&wlWm.photonTimings);
+
+  for (;;)
+  {
+    struct WaylandPresentationFrame * frame = NULL;
+    struct wp_presentation_feedback * feedback = NULL;
+    struct PresentationCompletion      completion = {};
+
+    LG_LOCK(wlWm.presentationLock);
+    if (!wl_list_empty(&wlWm.presentationFrames))
+    {
+      frame = wl_container_of(
+          wlWm.presentationFrames.next, frame, link);
+      wl_list_remove(&frame->link);
+      feedback             = frame->feedback;
+      frame->feedback      = NULL;
+      frame->swapDone      = true;
+      frame->swapValid     = false;
+      frame->feedbackDone  = true;
+      frame->feedbackValid = false;
+      presentationCompleteLocked(frame, &completion);
+    }
+    LG_UNLOCK(wlWm.presentationLock);
+
+    if (!frame)
+      break;
+
+    presentationNotify(&completion);
+    wp_presentation_feedback_destroy(feedback);
+    presentationFrameRelease(frame);
+  }
+
+  if (wlWm.presentation)
+  {
+    wp_presentation_destroy(wlWm.presentation);
+    wlWm.presentation = NULL;
+    app_unregisterGraph(wlWm.photonGraph);
+    ringbuffer_free(&wlWm.photonTimings);
+  }
+  LG_LOCK_FREE(wlWm.presentationLock);
 }
 
-void waylandPresentationFrame(void)
+struct WaylandPresentationFrame * waylandPresentationFrame(
+    uint64_t frameToken)
 {
   if (!wlWm.presentation || !atomic_load_explicit(
         &wlWm.presentationClockValid, memory_order_acquire))
-    return;
+    return NULL;
 
-  struct FrameData * data = malloc(sizeof(*data));
-  if (!data)
+  struct WaylandPresentationFrame * frame = calloc(1, sizeof(*frame));
+  if (!frame)
   {
     DEBUG_ERROR("out of memory");
-    return;
+    return NULL;
   }
 
-  if (clock_gettime(wlWm.clkId, &data->sent))
+  if (clock_gettime(wlWm.clkId, &frame->sent))
   {
-    DEBUG_ERROR("clock_gettime failed: %s\n", strerror(errno));
-    free(data);
-    return;
+    DEBUG_ERROR("clock_gettime failed: %s", strerror(errno));
+    free(frame);
+    return NULL;
   }
 
-  struct wp_presentation_feedback * feedback = wp_presentation_feedback(wlWm.presentation, wlWm.surface);
-  wp_presentation_feedback_add_listener(feedback, &presentationFeedbackListener, data);
+  frame->feedback =
+    wp_presentation_feedback(wlWm.presentation, wlWm.surface);
+  if (!frame->feedback)
+  {
+    free(frame);
+    return NULL;
+  }
+
+  frame->frameToken     = frameToken;
+  frame->timingComplete = frameToken == 0;
+  atomic_init(&frame->refs, 2);
+  if (wp_presentation_feedback_add_listener(frame->feedback,
+        &presentationFeedbackListener, frame) < 0)
+  {
+    wp_presentation_feedback_destroy(frame->feedback);
+    free(frame);
+    return NULL;
+  }
+
+  INTERLOCKED_SECTION(wlWm.presentationLock,
+  {
+    wl_list_insert(&wlWm.presentationFrames, &frame->link);
+  });
+  return frame;
+}
+
+void waylandPresentationSwapDone(struct WaylandPresentationFrame * frame,
+    bool result, bool * presentTracked)
+{
+  *presentTracked = false;
+  if (!frame)
+    return;
+
+  struct timespec swapReturn = {};
+  const bool      swapValid  = result &&
+    clock_gettime(wlWm.clkId, &swapReturn) == 0;
+  if (result && !swapValid)
+    DEBUG_ERROR("clock_gettime failed: %s", strerror(errno));
+
+  struct PresentationCompletion completion = {};
+  INTERLOCKED_SECTION(wlWm.presentationLock,
+  {
+    frame->swapDone   = true;
+    frame->swapValid  = swapValid;
+    frame->swapReturn = swapReturn;
+
+    if (!swapValid && !frame->timingComplete)
+    {
+      frame->timingComplete  = true;
+      completion.notify      = true;
+      completion.frameToken  = frame->frameToken;
+      completion.presentTime = 0;
+      completion.valid       = false;
+    }
+    else
+      presentationCompleteLocked(frame, &completion);
+  });
+
+  *presentTracked = result && frame->frameToken != 0;
+  presentationNotify(&completion);
+  presentationFrameRelease(frame);
 }