[LTP] [PATCH] clock_gettime04: relax the time diff in VM

[Li Wang <liwang@redhat.com>]

To balance that the test inside a VM can NOT get enough CPU time, which
result in sporadically fails with the time comparing.

clock_gettime04.c:155: PASS: CLOCK_REALTIME: Difference between successive readings is reasonable
clock_gettime04.c:155: PASS: CLOCK_REALTIME_COARSE: Difference between successive readings is reasonable
clock_gettime04.c:148: FAIL: CLOCK_MONOTONIC: Difference between successive readings greater than 5 ms (2): 22
clock_gettime04.c:155: PASS: CLOCK_MONOTONIC_COARSE: Difference between successive readings is reasonable
clock_gettime04.c:148: FAIL: CLOCK_MONOTONIC_RAW: Difference between successive readings greater than 5 ms (1): 22
clock_gettime04.c:148: FAIL: CLOCK_BOOTTIME: Difference between successive readings greater than 5 ms (1): 29

Signed-off-by: Li Wang <liwang@redhat.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
---
 .../kernel/syscalls/clock_gettime/clock_gettime04.c      | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/testcases/kernel/syscalls/clock_gettime/clock_gettime04.c b/testcases/kernel/syscalls/clock_gettime/clock_gettime04.c
index 2f484c43f..5c4a5d751 100644
--- a/testcases/kernel/syscalls/clock_gettime/clock_gettime04.c
+++ b/testcases/kernel/syscalls/clock_gettime/clock_gettime04.c
@@ -92,6 +92,7 @@ static void run(unsigned int i)
 	struct test_variants *tv;
 	int count = 10000, ret;
 	unsigned int j;
+	int virt_env = tst_is_virt(VIRT_ANY);
 
 	do {
 		for (j = 0; j < ARRAY_SIZE(variants); j++) {
@@ -143,11 +144,17 @@ static void run(unsigned int i)
 
 			diff /= 1000000;
 
-			if (diff >= 5) {
+			if (!virt_env && diff >= 5) {
 				tst_res(TFAIL, "%s: Difference between successive readings greater than 5 ms (%d): %lld",
 					tst_clock_name(clks[i]), j, diff);
 				return;
 			}
+
+			if (virt_env && diff >= 50) {
+				tst_res(TFAIL, "%s: Difference between successive readings(in VM) greater than 50 ms (%d): %lld",
+					tst_clock_name(clks[i]), j, diff);
+				return;
+			}
 		}
 	} while (--count);
 
-- 
2.21.3