timeline: Add GPU timestamp timepoint argument

The purpose of this argument is to hold timestamp information about
events that occurred on the GPU. This argument allows us to include GPU
timestamps in timepoints such as the beginning and end of frame
rendering.

Signed-off-by: Alexandros Frantzis <alexandros.frantzis@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>

libweston/timeline.c

@@ -232,12 +232,24 @@ emit_vblank_timestamp(struct timeline_emit_context *ctx, void *obj)
 	return 1;
 }
 
+static int
+emit_gpu_timestamp(struct timeline_emit_context *ctx, void *obj)
+{
+	struct timespec *ts = obj;
+
+	fprintf(ctx->cur, "\"gpu\":[%" PRId64 ", %ld]",
+		(int64_t)ts->tv_sec, ts->tv_nsec);
+
+	return 1;
+}
+
 typedef int (*type_func)(struct timeline_emit_context *ctx, void *obj);
 
 static const type_func type_dispatch[] = {
 	[TLT_OUTPUT] = emit_weston_output,
 	[TLT_SURFACE] = emit_weston_surface,
 	[TLT_VBLANK] = emit_vblank_timestamp,
+	[TLT_GPU] = emit_gpu_timestamp,
 };
 
 WL_EXPORT void

libweston/timeline.h

@@ -42,6 +42,7 @@ enum timeline_type {
 	TLT_OUTPUT,
 	TLT_SURFACE,
 	TLT_VBLANK,
+	TLT_GPU,
 };
 
 #define TYPEVERIFY(type, arg) ({			\
@@ -53,6 +54,7 @@ enum timeline_type {
 #define TLP_OUTPUT(o) TLT_OUTPUT, TYPEVERIFY(struct weston_output *, (o))
 #define TLP_SURFACE(s) TLT_SURFACE, TYPEVERIFY(struct weston_surface *, (s))
 #define TLP_VBLANK(t) TLT_VBLANK, TYPEVERIFY(const struct timespec *, (t))
+#define TLP_GPU(t) TLT_GPU, TYPEVERIFY(const struct timespec *, (t))
 
 #define TL_POINT(...) do { \
 	if (weston_timeline_enabled_) \