1 files changed, 104 insertions, 0 deletions
diff --git a/src/vppinfra/test_time.c b/src/vppinfra/test_time.c
new file mode 100644
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+++ b/src/vppinfra/test_time.c
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+/*
+ * Copyright (c) 2015 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/*
+  Copyright (c) 2005 Eliot Dresselhaus
+
+  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 <vppinfra/format.h>
+#include <vppinfra/time.h>
+#include <vppinfra/math.h>	/* for sqrt */
+
+static int verbose;
+#define if_verbose(format,args...) \
+  if (verbose) { clib_warning(format, ## args); }
+
+static int
+test_time_main (unformat_input_t * input)
+{
+  f64 wait, error;
+  f64 t, tu[3], ave, rms;
+  clib_time_t c;
+  int i, n, j;
+
+  clib_time_init (&c);
+  wait = 1e-3;
+  n = 1000;
+  unformat (input, "%f %d", &wait, &n);
+  ave = rms = 0;
+  tu[0] = unix_time_now ();
+  tu[1] = unix_time_now ();
+  for (i = 0; i < n; i++)
+    {
+      j = 0;
+      t = clib_time_now (&c);
+      while (clib_time_now (&c) < t + wait)
+	j++;
+      t = j;
+      ave += t;
+      rms += t * t;
+    }
+  tu[2] = unix_time_now ();
+  ave /= n;
+  rms = sqrt (rms / n - ave * ave);
+
+  error = ((tu[2] - tu[1]) - 2 * (tu[1] - tu[0]) - n * wait) / n;
+  if_verbose ("tested %d x %.6e sec waits, error %.6e loops %.6e +- %.6e\n",
+	      n, wait, error, ave, rms);
+
+  return 0;
+}
+
+#ifdef CLIB_UNIX
+int
+main (int argc, char *argv[])
+{
+  unformat_input_t i;
+  int ret;
+
+  verbose = (argc > 1);
+  unformat_init_command_line (&i, argv);
+  ret = test_time_main (&i);
+  unformat_free (&i);
+
+  return ret;
+}
+#endif /* CLIB_UNIX */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */