From: Dmitry V. Levin <ldv@altlinux.org>
Date: Sun, 6 Dec 2015 04:51:57 +0000 (+0000)
Subject: times.test: reduce cpu time consumption, increase struct tms diversity
X-Git-Tag: v4.11~54
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=fc0a22d40b2e40d9a25e5f3c30e0144b8a15898f;p=strace

times.test: reduce cpu time consumption, increase struct tms diversity

* tests/times.c (main): Reduce cpu time consumption fourfold,
make the parent process consume less cpu time than the child process
so that members of the structure returned by times syscall would be
more likely to contain different values.
---

diff --git a/tests/times.c b/tests/times.c
index 8bdb0ef5..0ec30198 100644
--- a/tests/times.c
+++ b/tests/times.c
@@ -18,37 +18,37 @@
 
 enum {
 	NUM_USER_ITERS = 1000000,
-	CPUTIME_LIMIT_SEC = 2,
+	PARENT_CPUTIME_LIMIT_NSEC = 200000000,
+	CHILD_CPUTIME_LIMIT_NSEC = 300000000
 };
 
 int
 main (void)
 {
-	struct tms tbuf;
 	struct timespec ts;
-	clock_t res;
-	unsigned long long llres;
 	volatile int dummy;
-	pid_t pid;
 	int i;
 
-	pid = fork();
+	pid_t pid = fork();
 
 	if (pid < 0)
 		return 77;
 
+	const long cputime_limit =
+		pid ? PARENT_CPUTIME_LIMIT_NSEC : CHILD_CPUTIME_LIMIT_NSEC;
+
 	/* Enjoying my user time */
 	while (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts) == 0) {
-		if (ts.tv_sec >= CPUTIME_LIMIT_SEC)
+		if (ts.tv_sec || ts.tv_nsec >= cputime_limit)
 			break;
 
-		for (i = 0; i < NUM_USER_ITERS; i++, dummy++)
-			;
+		for (i = 0; i < NUM_USER_ITERS; ++i)
+			++dummy;
 	}
 
 	/* Enjoying my system time */
 	while (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts) == 0) {
-		if (ts.tv_sec >= (CPUTIME_LIMIT_SEC * 2))
+		if (ts.tv_sec || ts.tv_nsec >= cputime_limit * 2)
 			break;
 
 		sched_yield();
@@ -60,11 +60,13 @@ main (void)
 		wait(NULL);
 	}
 
-	res = times(&tbuf);
+	struct tms tbuf;
+	clock_t res = times(&tbuf);
 
 	if (res == (clock_t) -1)
 		return 77;
 
+	unsigned long long llres;
 	if (sizeof(llres) > sizeof(res))
 		llres = (unsigned long) res;
 	else