From fdb2baa10a02a29c44c209897527e84d2fc78349 Mon Sep 17 00:00:00 2001
From: Josarn <josuaarndt@live.de>
Date: Tue, 24 Jul 2018 02:04:12 +0200
Subject: [PATCH] test/xtimer_drift: interval calculation
---
tests/xtimer_drift/main.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/tests/xtimer_drift/main.c b/tests/xtimer_drift/main.c
index 814800e575..dcdfa77c8c 100644
--- a/tests/xtimer_drift/main.c
+++ b/tests/xtimer_drift/main.c
@@ -91,6 +91,10 @@ void *worker_thread(void *arg)
{
(void) arg;
+ /* Calculate interval based on possible precision when 'XTIMER_SHIFT > 0',
+ * to apply precision loss to expected interval length.
+ * test_interval != TEST_INTERVAL */
+ uint32_t test_interval = xtimer_usec_from_ticks(xtimer_ticks_from_usec(TEST_INTERVAL));
uint32_t loop_counter = 0;
uint32_t start = 0;
uint32_t last = 0;
@@ -111,14 +115,14 @@ void *worker_thread(void *arg)
else if ((loop_counter % TEST_HZ) == 0) {
uint32_t us = now % US_PER_SEC;
uint32_t sec = now / US_PER_SEC;
- uint32_t expected = start + loop_counter * TEST_INTERVAL;
+ uint32_t expected = start + loop_counter * test_interval;
int32_t drift = now - expected;
- expected = last + TEST_HZ * TEST_INTERVAL;
+ expected = last + TEST_HZ * test_interval;
int32_t jitter = now - expected;
printf("now=%" PRIu32 ".%06" PRIu32 " (0x%08" PRIx32 " ticks), ",
- sec, us, ticks.ticks32);
+ sec, us, ticks.ticks32);
printf("drift=%" PRId32 " us, jitter=%" PRId32 " us\n",
- drift, jitter);
+ drift, jitter);
last = now;
}
++loop_counter;
--
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