[LTP] [PATCH] tst_timer: fix verification of execution time

[Piotr Gawel]

Each sample needs to be in range:
    t < s[i] < t + threshold
Thus for i from the interval [d...n]:
    (n-d)*t < sum(s[d...n]) < (n-d)*(t + threshold)
This patch fixes that check.

Signed-off-by: Piotr Gawel <piotr.krzysztof.gawel@gmail.com>
---
 lib/tst_timer_test.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/tst_timer_test.c b/lib/tst_timer_test.c
index f6459e5..4508e29 100644
--- a/lib/tst_timer_test.c
+++ b/lib/tst_timer_test.c
@@ -306,7 +306,7 @@ void do_timer_test(long long usec, unsigned int nsamples)
 		samples[nsamples-1], samples[0], median,
 		1.00 * trunc_mean / keep_samples, discard);
 
-	if (trunc_mean > (nsamples - discard) * usec + threshold) {
+	if (trunc_mean > keep_samples * (usec + threshold)) {
 		tst_res(TFAIL, "%s slept for too long", scall);
 
 		if (!print_frequency_plot)
-- 
2.7.4