From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 047FC239E9D for ; Fri, 14 Nov 2025 00:34:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763080482; cv=none; b=o/hDmSqUOMtWOKI8R03OPTg0LHkjfpNyLcKKE8fW17CNYcACvNgXtiuoMnyGCLwFCEokSZETICIKBcJulICTuMAPJPmFH3m1cjlnv2/PgtLDdu/yY59LUX1cnSRHjX/6aQmukJ3lL64n5yezScw2SLexS9F1Sq4/BDd7XjRcwO0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763080482; c=relaxed/simple; bh=h4IIGtUwg2zfQLlgqSuzTJ14YwbK9UnHqRaoE6Y4Amw=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=iWBxnJw0PDCtJQgH22ZNMW60gyJ2yBpnuoZtfu8ojL4TFamFDGbF3ZgVixRn8PV1Cufb6fwT9/F7ZHiQLfs+TZq4IzOY4I1uGeDXxgS7uAFBxJzSRGJ/MLeHQPnil791k/mW6tmt347OlLWOtKk7tQPBEQHXYzzsyXXQG8vwZlU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=OUC2+or0; arc=none smtp.client-ip=209.85.216.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="OUC2+or0" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-3418ad76023so3531874a91.0 for ; Thu, 13 Nov 2025 16:34:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1763080480; x=1763685280; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=+LHuB8xIRgaS8JdU4+Im4g3U/MNFjG6h6raen6xbSHw=; b=OUC2+or0QrpYj80HnsJipfY1AGYBgOUnsYc4sxhuFeQgMbmXmd3uIjCVmEOQmVgp98 GjQ0gHVUewOAWdgTe2mby9PSWhy6/vRruKgMyb31Ij7ZjkOB5YbAObT3i3pQvXgNI4o7 Mx4UdiQm3qt3LH0guOkrFd6YZJZYmuc+F8FXz+FWCaNUwN9sSykutMz6v30sE8dsjgpz UZDs0b5qdo5CjDBkSXy1SWJH5L4eJtcFnHe7DLQZ//n0lgCSiId/sWHvIKDlTS4Ds1JC /eqYTn+PtCqsny9SsMWRyHxOv4hS2LExMe344/ylWnFCdGTsWLKBsh62U2UjTa5WdhNh oSKQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763080480; x=1763685280; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=+LHuB8xIRgaS8JdU4+Im4g3U/MNFjG6h6raen6xbSHw=; b=ow08Gx7MZIwDalUyUxtXCgm/Q/Xj+DQrkxsvp3RnWHbxSCTHhEK3vsAQ4gQIuemNcF C52zUz69onodE+3OipVLFKKUDU7iDVaRyEQnCOU48q9DcU6bLp1Idk6JLi+pfbpMX1Ys uGwrQpsk5S+7lu3TRYpz7m35XfgfmAHhctVHLqH0zuuOp2Cxpi1Hc8/P7na6Y0tjWBUH ruv4dSZAY+fcZGeI7E9gQ6hsPDOFHIrWFqfXshhyBMzHa+tUMjG/Zz8kXSZtPOltq+VX J6g0ElxxtDZdFuDiwGEyhejj1lr8lGrsWI880fux8+nItfeHe6P2DKgpvwdv+upW5V8y gz/Q== X-Forwarded-Encrypted: i=1; AJvYcCWJqGn1xZzTlc9+6z0f8BL3qBdAiUmCC/YeQ9MDit1dj3gH2RgfQtXolQHIBqxIX3c9bIBJebZDqE2fwzQ=@vger.kernel.org X-Gm-Message-State: AOJu0YyZ7XoM4Ga1zJV86jtGt7DWKG2+Q1UWZYFt3U6RrNW3hlqokNvV zpPW+Rl3rJFb3rXeDHyO/YzkPrdoX6JLDBb7POlMl3rovae9/HihPmft8lUp8iVDc8sNquagsts h55CKSg== X-Google-Smtp-Source: AGHT+IGMe9Nh974AZHgvnwuhOflFpS2qGBRz4ejDlIY+jCOIYlRX8kP36jsF47mvsnpylL4SvqRZOZBbBJg= X-Received: from pjbms19.prod.google.com ([2002:a17:90b:2353:b0:341:7640:eb1e]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:35d0:b0:33b:cfae:3621 with SMTP id 98e67ed59e1d1-343fa7611b6mr1152459a91.32.1763080480391; Thu, 13 Nov 2025 16:34:40 -0800 (PST) Date: Thu, 13 Nov 2025 16:34:35 -0800 In-Reply-To: <20251110232642.633672-10-yosry.ahmed@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251110232642.633672-1-yosry.ahmed@linux.dev> <20251110232642.633672-10-yosry.ahmed@linux.dev> Message-ID: Subject: Re: [PATCH v3 09/14] x86/svm: Deflake svm_tsc_scale_test From: Sean Christopherson To: Yosry Ahmed Cc: Paolo Bonzini , Kevin Cheng , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" 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