[PATCH] cyclictest: fix accumulating overruns in periodic timer mode

[PATCH] cyclictest: fix accumulating overruns in periodic timer mode

[Michal Schmidt]

When using a POSIX interval timer and an overrun occurs, a signal is always
lost. From then on cyclictest would report all measurements as increased by
N*period (where N is the number of overruns).

cyclictest can detect the overruns and adjust the expected time of the next
tick accordingly.

Reported-by: Marti Raudsepp <marti@juffo.org>
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
---

 src/cyclictest/cyclictest.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
index 3a7e752..6829d34 100644
--- a/src/cyclictest/cyclictest.c
+++ b/src/cyclictest/cyclictest.c
@@ -713,6 +713,11 @@ void *timerthread(void *param)
 
 		next.tv_sec += interval.tv_sec;
 		next.tv_nsec += interval.tv_nsec;
+		if (par->mode == MODE_CYCLIC) {
+			int overrun_count = timer_getoverrun(timer);
+			next.tv_sec += overrun_count * interval.tv_sec;
+			next.tv_nsec += overrun_count * interval.tv_nsec;
+		}
 		tsnorm(&next);
 
 		if (par->max_cycles && par->max_cycles == stat->cycles)