gallium/util: add easy profiling helpers using TIME_ELAPSED queries

There are no users and that's intentional.

Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10262>

src/gallium/auxiliary/util/u_helpers.c

@@ -218,6 +218,33 @@ util_end_pipestat_query(struct pipe_context *ctx, struct pipe_query *q,
            stats.cs_invocations);
 }
 
+/* This is a helper for profiling. Don't remove. */
+struct pipe_query *
+util_begin_time_query(struct pipe_context *ctx)
+{
+   struct pipe_query *q =
+      ctx->create_query(ctx, PIPE_QUERY_TIME_ELAPSED, 0);
+   if (!q)
+      return NULL;
+
+   ctx->begin_query(ctx, q);
+   return q;
+}
+
+/* This is a helper for profiling. Don't remove. */
+void
+util_end_time_query(struct pipe_context *ctx, struct pipe_query *q, FILE *f,
+                    const char *name)
+{
+   union pipe_query_result result;
+
+   ctx->end_query(ctx, q);
+   ctx->get_query_result(ctx, q, true, &result);
+   ctx->destroy_query(ctx, q);
+
+   fprintf(f, "Time elapsed: %s - %"PRIu64".%u us\n", name, result.u64 / 1000, (unsigned)(result.u64 % 1000) / 100);
+}
+
 /* This is a helper for hardware bring-up. Don't remove. */
 void
 util_wait_for_idle(struct pipe_context *ctx)

src/gallium/auxiliary/util/u_helpers.h

@@ -87,6 +87,12 @@ void
 util_end_pipestat_query(struct pipe_context *ctx, struct pipe_query *q,
                         FILE *f);
 
+struct pipe_query *
+util_begin_time_query(struct pipe_context *ctx);
+void
+util_end_time_query(struct pipe_context *ctx, struct pipe_query *q, FILE *f,
+                    const char *name);
+
 void
 util_wait_for_idle(struct pipe_context *ctx);