+/* Timer query */
+typedef struct timer_query
+{
+ unsigned id;
+
+ metrics_op_t op;
+ struct timer_query *next;
+} timer_query_t;
+
+/* Performance-monitor query */
+typedef struct monitor
+{
+ unsigned id;
+
+ metrics_op_t op;
+ struct monitor *next;
+} monitor_t;
+
+typedef struct op_metrics
+{
+ /* This happens to also be the index into the
+ * metrics->op_metrics array currently
+ */
+ metrics_op_t op;
+ double time_ns;
+
+ double **counters;
+} op_metrics_t;
+
+struct metrics
+{
+ /* Flag to indicate first frame is being processed. */
+ bool first_frame;
+
+ /* Description of all available peformance counters, counter
+ * groups, their names and IDs, etc. */
+ metrics_info_t *info;
+
+ /* The current operation being measured. */
+ metrics_op_t op;
+
+ /* GL_TIME_ELAPSED query for which glEndQuery has not yet
+ * been called. */
+ unsigned timer_begun_id;
+
+ /* GL_TIME_ELAPSED queries for which glEndQuery has been
+ * called, (but results have not yet been queried). */
+ timer_query_t *timer_head;
+ timer_query_t *timer_tail;
+
+ /* Performance monitor for which glEndPerfMonitorAMD has not
+ * yet been called. */
+ unsigned monitor_begun_id;
+
+ /* Performance monitors for which glEndPerfMonitorAMD has
+ * been called, (but results have not yet been queried). */
+ monitor_t *monitor_head;
+ monitor_t *monitor_tail;
+
+ int monitors_in_flight;
+
+ unsigned num_op_metrics;
+ op_metrics_t *op_metrics;
+
+ /* Per-frame time and latency measurement. */
+ GLint64 swap_begin_timestamp;
+ unsigned swap_end_timestamp_id;
+ GLint64 previous_swap_end_timestamp;
+
+ struct timespec previous_cpu_time_ts;
+ struct timespec cpu_time_ts;
+};
+
+/* Return (a - b) while accounting for the fact that between a and b,
+ * the counter may have wrapped around (with a maximum number of bits
+ * in the counter of GL_QUERY_COUNTER_BITS). */
+static uint64_t
+subtract_timestamp (uint64_t a, uint64_t b)
+{
+ GLint timestamp_bits;
+
+ glGetQueryiv (GL_TIMESTAMP, GL_QUERY_COUNTER_BITS, ×tamp_bits);
+
+ /* Note: "<<" isn't defined for the number of bits in the
+ * type, and the compiler will punish you.
+ */
+ if (timestamp_bits == 64)
+ return a - b;
+
+ if (b > a)
+ return (1ull << timestamp_bits) + a - b;
+ else
+ return a - b;
+}
+
+metrics_t *
+metrics_create (metrics_info_t *info)
+{
+ metrics_t *metrics;
+
+ metrics = xmalloc (sizeof (metrics_t));
+
+ metrics->info = info;
+
+ metrics->first_frame = true;
+
+ metrics->op = 0;
+
+ metrics->timer_begun_id = 0;
+
+ metrics->timer_head = NULL;
+ metrics->timer_tail = NULL;
+
+ metrics->monitor_begun_id = 0;
+
+ metrics->monitor_head = NULL;
+ metrics->monitor_tail = NULL;
+
+ metrics->monitors_in_flight = 0;
+
+ metrics->num_op_metrics = 0;
+ metrics->op_metrics = NULL;
+
+ glGenQueries (1, &metrics->swap_end_timestamp_id);
+
+ /* Get the first frame timestamp started immediately. */
+ glQueryCounter (metrics->swap_end_timestamp_id, GL_TIMESTAMP);
+
+ /* As well as the initial CPU time. */
+ clock_gettime (CLOCK_PROCESS_CPUTIME_ID, &metrics->cpu_time_ts);
+
+ return metrics;
+}
+
+void
+metrics_fini (metrics_t *metrics)
+{
+ timer_query_t *timer, *timer_next;
+ monitor_t *monitor, *monitor_next;
+
+ /* Discard and cleanup any outstanding queries. */
+ if (metrics->timer_begun_id) {
+ glDeleteQueries (1, &metrics->timer_begun_id);
+ metrics->timer_begun_id = 0;
+ }
+
+ for (timer = metrics->timer_head;
+ timer;
+ timer = timer_next)
+ {
+ glDeleteQueries (1, &timer->id);
+ timer_next = timer->next;
+ free (timer);
+ }
+ metrics->timer_head = NULL;
+ metrics->timer_tail = NULL;
+
+ if (metrics->info->have_perfmon) {
+
+ if (metrics->monitor_begun_id) {
+ glDeletePerfMonitorsAMD (1, &metrics->monitor_begun_id);
+ metrics->monitor_begun_id = 0;
+ }
+
+ for (monitor = metrics->monitor_head;
+ monitor;
+ monitor = monitor_next)
+ {
+ glDeletePerfMonitorsAMD (1, &monitor->id);
+ monitor_next = monitor->next;
+ free (monitor);
+ }
+ metrics->monitor_head = NULL;
+ metrics->monitor_tail = NULL;
+
+ }
+
+ metrics->monitors_in_flight = 0;
+}
+
+void
+metrics_destroy (metrics_t *metrics)
+{
+ metrics_fini (metrics);
+
+ free (metrics);
+}
+