1 files changed, 96 insertions, 0 deletions

diff --git a/src/lib/util/test_scheduler_delay.c b/src/lib/util/test_scheduler_delay.c
new file mode 100644
index 000000000..41990272a
--- /dev/null
+++ b/src/lib/util/test_scheduler_delay.c
@@ -0,0 +1,96 @@
+/*
+     This file is part of GNUnet.
+     Copyright (C) 2001-2013 GNUnet e.V.
+
+     GNUnet is free software: you can redistribute it and/or modify it
+     under the terms of the GNU Affero General Public License as published
+     by the Free Software Foundation, either version 3 of the License,
+     or (at your option) any later version.
+
+     GNUnet is distributed in the hope that it will be useful, but
+     WITHOUT ANY WARRANTY; without even the implied warranty of
+     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+     Affero General Public License for more details.
+
+     You should have received a copy of the GNU Affero General Public License
+     along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+/**
+ * @file util/test_scheduler_delay.c
+ * @brief testcase for delay of scheduler, measures how
+ *  precise the timers are.  Expect values between 0.2 and 2 ms on
+ *  modern machines.
+ */
+
+#include "platform.h"
+#include "gnunet_util_lib.h"
+
+static struct GNUNET_TIME_Absolute target;
+
+static int i;
+
+static unsigned long long cumDelta;
+
+#define INCR 47
+
+#define MAXV 5000
+
+
+/**
+ * Signature of the main function of a task.
+ *
+ * @param cls closure
+ */
+static void
+test_task (void *cls)
+{
+  struct GNUNET_TIME_Absolute now;
+
+  now = GNUNET_TIME_absolute_get ();
+  if (now.abs_value_us > target.abs_value_us)
+    cumDelta += (now.abs_value_us - target.abs_value_us);
+  else
+    cumDelta += (target.abs_value_us - now.abs_value_us);
+  target =
+    GNUNET_TIME_relative_to_absolute (GNUNET_TIME_relative_multiply
+                                        (GNUNET_TIME_UNIT_MICROSECONDS, i));
+  fprintf (stderr, "%s", ".");
+  if (i > MAXV)
+  {
+    fprintf (stderr, "%s", "\n");
+    return;
+  }
+  GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_relative_multiply
+                                  (GNUNET_TIME_UNIT_MICROSECONDS, i),
+                                &test_task,
+                                NULL);
+  i += INCR;
+}
+
+
+int
+main (int argc, char *argv[])
+{
+  GNUNET_log_setup ("test-scheduler-delay",
+                    "WARNING",
+                    NULL);
+  target = GNUNET_TIME_absolute_get ();
+  GNUNET_SCHEDULER_run (&test_task, NULL);
+  fprintf (stdout,
+           "Sleep precision: %llu microseconds (average delta). ",
+           cumDelta / (MAXV / INCR));
+  if (cumDelta <= 500 * MAXV / INCR)
+    fprintf (stdout, "%s", "Timer precision is excellent.\n");
+  else if (cumDelta <= 5000 * MAXV / INCR)        /* 5 ms average deviation */
+    fprintf (stdout, "%s", "Timer precision is good.\n");
+  else if (cumDelta > 25000 * MAXV / INCR)
+    fprintf (stdout, "%s", "Timer precision is awful.\n");
+  else
+    fprintf (stdout, "%s", "Timer precision is acceptable.\n");
+  return 0;
+}
+
+
+/* end of test_scheduler_delay.c */