From: Eugene Syromyatnikov <evgsyr@gmail.com>
Date: Fri, 11 Oct 2019 11:36:15 +0000 (+0200)
Subject: tests: try to avoid false positives in times sanity check
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=c5ed146fa97cf50b11c6fcf9181e2fc501e245f8;p=strace

tests: try to avoid false positives in times sanity check

Checking clock_gettime(CLOCK_PROCESS_CPUTIME_ID) starting from the
second iteration may produce false positives sometimes, try to spend
more iterations before starting checking it.

* tests/times.c (NUM_USER_ITERS_SQRT): New enum entity.
(NUM_USER_ITERS): Define via NUM_USER_ITERS_SQRT.
(main): Check i against NUM_USER_ITERS_SQRT first before checking
the returned CPU time for sanity.
---

diff --git a/tests/times.c b/tests/times.c
index 4f7e361e..06a0f257 100644
--- a/tests/times.c
+++ b/tests/times.c
@@ -24,7 +24,8 @@
 #include <sys/wait.h>
 
 enum {
-	NUM_USER_ITERS = 1000000,
+	NUM_USER_ITERS_SQRT = 1000,
+	NUM_USER_ITERS = NUM_USER_ITERS_SQRT * NUM_USER_ITERS_SQRT,
 	PARENT_CPUTIME_LIMIT_NSEC = 200000000,
 	CHILD_CPUTIME_LIMIT_NSEC = 300000000
 };
@@ -48,7 +49,7 @@ main(void)
 		if (ts.tv_sec || ts.tv_nsec >= cputime_limit)
 			break;
 
-		if (i && !(ts.tv_sec || ts.tv_nsec))
+		if ((i > NUM_USER_ITERS_SQRT) && !(ts.tv_sec || ts.tv_nsec))
 			error_msg_and_skip("clock_gettime(CLOCK_PROCESS_CPUTIME_ID, {0, 0})");
 
 		for (i = 0; i < NUM_USER_ITERS; ++i)