From: Yosry Ahmed <yosry.ahmed@linux.dev>
To: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Jim Mattson <jmattson@google.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Yosry Ahmed <yosry.ahmed@linux.dev>
Subject: [kvm-unit-tests 4/4] x86/svm: Deflake svm_tsc_scale_test
Date: Tue, 4 Nov 2025 19:30:16 +0000 [thread overview]
Message-ID: <20251104193016.3408754-5-yosry.ahmed@linux.dev> (raw)
In-Reply-To: <20251104193016.3408754-1-yosry.ahmed@linux.dev>
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 8d309860e76e5..29c899762b7a4 100644
--- a/x86/svm_tests.c
+++ b/x86/svm_tests.c
@@ -1002,7 +1002,7 @@ 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)
--
2.51.2.1026.g39e6a42477-goog
prev parent reply other threads:[~2025-11-04 19:31 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-04 19:30 [kvm-unit-tests 0/4] Misc fixups/cleanups for nested tests Yosry Ahmed
2025-11-04 19:30 ` [kvm-unit-tests 1/4] x86/vmx: Skip vmx_pf_exception_test_fep early if FEP is not available Yosry Ahmed
2025-11-04 19:30 ` [kvm-unit-tests 2/4] x86/svm: Print SVM test names before running tests Yosry Ahmed
2025-11-04 19:30 ` [kvm-unit-tests 3/4] x86/svm: Replace #UD on failure in LBRV tests with proper report()s Yosry Ahmed
2025-11-04 19:30 ` Yosry Ahmed [this message]
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