[PATCH v3 09/14] x86/svm: Deflake svm_tsc_scale_test

Yosry Ahmed
2025-11-10T23:27:17Z

On an AMT Turin (EPYC Zen 5), svm_tsc_scale_test flakes on the last test
case with 0.0001 TSC scaling ratio, even with the 24-bit shift for
stability. On failure, the actual value is 49 instead of the expected
50.

Use a higher scaling ratio, 0.001, which makes the test pass
consistently.

Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
---
x86/svm_tests.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/x86/svm_tests.c b/x86/svm_tests.c
index 61ab63db462dc..1e7556a37adec 100644
--- a/x86/svm_tests.c
+++ b/x86/svm_tests.c
@@ -943,7 +943,7 @@ static void svm_tsc_scale_test(void)
}

svm_tsc_scale_run_testcase(50, 255, rdrand());
- svm_tsc_scale_run_testcase(50, 0.0001, rdrand());
+ svm_tsc_scale_run_testcase(50, 0.001, rdrand());
}

static void latency_prepare(struct svm_test *test)
--
2.51.2.1041.gc1ab5b90ca-goog