Fix time/tst-cpuclock1 intermitent failures

This test fails intermittently in systems with heavy load as
CLOCK_PROCESS_CPUTIME_ID is subject to scheduler pressure.  Thus the
test boundaries were relaxed to keep it from failing on such systems.

A refactor of the spent time checking was made with some support
functions.  With the advantage to representing time jitter in percent
of the target.

The values used by the test boundaries are all empirical.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 64 insertions, 0 deletions

diff --git a/support/timespec.c b/support/timespec.c
index ea6b947..9f5449e 100644
--- a/support/timespec.c
+++ b/support/timespec.c
@@ -19,6 +19,8 @@
 #include <support/timespec.h>
 #include <stdio.h>
 #include <stdint.h>
+#include <assert.h>
+#include <intprops.h>
 
 void
 test_timespec_before_impl (const char *file, int line,
@@ -57,3 +59,65 @@ test_timespec_equal_or_after_impl (const char *file, int line,
 	    (intmax_t) diff.tv_sec, (intmax_t) diff.tv_nsec);
   }
 }
+
+/* Convert TIME to nanoseconds stored in a long.
+   Returns long maximum or minimum if the conversion overflows
+   or underflows, respectively.  */
+long
+support_timespec_ns (struct timespec time)
+{
+  long time_ns;
+  if (INT_MULTIPLY_WRAPV(time.tv_sec, TIMESPEC_HZ, &time_ns))
+   {
+      return (time.tv_sec < 0) ? TYPE_MINIMUM(long): TYPE_MAXIMUM(long);
+   }
+  if (INT_ADD_WRAPV(time_ns, time.tv_nsec, &time_ns))
+   {
+      return (time.tv_nsec < 0) ? TYPE_MINIMUM(long): TYPE_MAXIMUM(long);
+   }
+  return time_ns;
+}
+
+/* Returns time normalized timespec with .tv_nsec < TIMESPEC_HZ
+   and the whole seconds  added to .tv_sec. If an overflow or
+   underflow occurs the values are clamped to its maximum or
+   minimum respectively.  */
+struct timespec
+support_timespec_normalize (struct timespec time)
+{
+  struct timespec norm;
+  if (INT_ADD_WRAPV (time.tv_sec, (time.tv_nsec / TIMESPEC_HZ), &norm.tv_sec))
+   {
+     norm.tv_sec = (time.tv_nsec < 0) ? TYPE_MINIMUM (time_t): TYPE_MAXIMUM (time_t);
+     norm.tv_nsec = (time.tv_nsec < 0) ? -1 * (TIMESPEC_HZ - 1) : TIMESPEC_HZ - 1;
+     return norm;
+   }
+  norm.tv_nsec = time.tv_nsec % TIMESPEC_HZ;
+  return norm;
+}
+
+/* Returns TRUE if the observed time is within the given percentage
+   bounds of the expected time, and FALSE otherwise.
+   For example the call
+
+   support_timespec_check_in_range(expected, observed, 0.5, 1.2);
+
+   will check if
+
+   0.5 of expected <= observed <= 1.2 of expected
+
+   In other words it will check if observed time is within 50% to
+   120% of the expected time.  */
+int
+support_timespec_check_in_range (struct timespec expected, struct timespec observed,
+			      double lower_bound, double upper_bound)
+{
+  assert (upper_bound >= lower_bound);
+  long expected_norm, observed_norm;
+  expected_norm = support_timespec_ns (expected);
+  /* Don't divide by zero  */
+  assert(expected_norm != 0);
+  observed_norm = support_timespec_ns (observed);
+  double ratio = (double)observed_norm / expected_norm;
+  return (lower_bound <= ratio && ratio <= upper_bound);
+}