vtest: use a poll fd if possible

For the same glmark2 "build" test, perf reports about half
instructions.

Signed-off-by: Marc-André Lureau <marcandre.lureau@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 46 insertions, 0 deletions

diff --git a/vtest/util.c b/vtest/util.c
new file mode 100644
index 0000000..0d3c78f
--- /dev/null
+++ b/vtest/util.c
@@ -0,0 +1,46 @@
+/**************************************************************************
+ *
+ * Copyright (C) 2016 Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+#include "util.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+int vtest_wait_for_fd_read(int fd)
+{
+   fd_set read_fds;
+
+   int ret;
+   FD_ZERO(&read_fds);
+   FD_SET(fd, &read_fds);
+
+   ret = select(fd + 1, &read_fds, NULL, NULL, NULL);
+   if (ret < 0)
+      return ret;
+
+   if (FD_ISSET(fd, &read_fds)) {
+      return 0;
+   }
+   return -1;
+}