From: Sean Christopherson <seanjc@google.com>
To: Yosry Ahmed <yosry.ahmed@linux.dev>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Kevin Cheng <chengkev@google.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 09/14] x86/svm: Deflake svm_tsc_scale_test
Date: Thu, 13 Nov 2025 16:34:35 -0800 [thread overview]
Message-ID: <aRZ5G6GSMnbHxx_K@google.com> (raw)
In-Reply-To: <20251110232642.633672-10-yosry.ahmed@linux.dev>
On Mon, Nov 10, 2025, Yosry Ahmed wrote:
> 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.
Top-tier analysis right here :-D
I'm going to take Jim's version instead of papering over the bug.
https://lore.kernel.org/all/CALMp9eQep3H-OtqmLe3O2MsOT-Vx4y0-LordKgN+pkp04VLSWw@mail.gmail.com
next prev parent reply other threads:[~2025-11-14 0:34 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-10 23:26 [PATCH v3 00/14] Improvements for (nested) SVM testing Yosry Ahmed
2025-11-10 23:26 ` [PATCH v3 01/14] scripts: Always return '2' when skipping tests Yosry Ahmed
2025-11-10 23:26 ` [PATCH v3 02/14] x86/vmx: Skip vmx_pf_exception_test_fep early if FEP is not available Yosry Ahmed
2025-11-14 0:40 ` Sean Christopherson
2025-11-14 0:47 ` Yosry Ahmed
2025-11-10 23:26 ` [PATCH v3 03/14] x86/svm: Cleanup selective cr0 write intercept test Yosry Ahmed
2025-11-12 13:48 ` Manali Shukla
2025-11-10 23:26 ` [PATCH v3 04/14] x86/svm: Move CR0 selective write intercept test near CR3 intercept Yosry Ahmed
2025-11-12 13:52 ` Manali Shukla
2025-11-10 23:26 ` [PATCH v3 05/14] x86/svm: Add FEP helpers for SVM tests Yosry Ahmed
2025-11-10 23:26 ` [PATCH v3 06/14] x86/svm: Report unsupported " Yosry Ahmed
2025-11-10 23:26 ` [PATCH v3 07/14] x86/svm: Move report_svm_guest() to the top of svm_tests.c Yosry Ahmed
2025-11-10 23:26 ` [PATCH v3 08/14] x86/svm: Print SVM test names before running tests Yosry Ahmed
2025-11-10 23:26 ` [PATCH v3 09/14] x86/svm: Deflake svm_tsc_scale_test Yosry Ahmed
2025-11-14 0:34 ` Sean Christopherson [this message]
2025-11-14 5:46 ` Yosry Ahmed
2025-11-10 23:26 ` [PATCH v3 10/14] x86/svm: Generalize and improve selective CR0 write intercept test Yosry Ahmed
2025-11-10 23:26 ` [PATCH v3 11/14] x86/svm: Add more selective CR0 write and LMSW test cases Yosry Ahmed
2025-11-10 23:26 ` [PATCH v3 12/14] x86/svm: Cleanup LBRV tests Yosry Ahmed
2025-11-13 11:58 ` Shivansh Dhiman
2025-11-13 14:59 ` Yosry Ahmed
2025-11-14 4:57 ` Shivansh Dhiman
2025-11-14 5:40 ` Yosry Ahmed
2025-11-10 23:26 ` [PATCH v3 13/14] x86/svm: Add more LBRV test cases Yosry Ahmed
2025-11-10 23:26 ` [PATCH v3 14/14] x86/svm: Rename VMCB fields to match KVM Yosry Ahmed
2025-11-14 0:40 ` Sean Christopherson
2025-11-11 0:52 ` [PATCH v3 00/14] Improvements for (nested) SVM testing Sean Christopherson
2025-11-11 0:58 ` Yosry Ahmed
2025-11-14 0:46 ` Sean Christopherson
2025-11-14 5:42 ` Yosry Ahmed
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