From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 28648D52B for ; Thu, 14 Dec 2023 07:14:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HZR21vmF" Received: by smtp.kernel.org (Postfix) with ESMTPS id 9F190C433C8 for ; Thu, 14 Dec 2023 07:14:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702538097; bh=Se9x4a4ij8zv5cOHcYMVXvSPw8yRlIsUqAPDoyY053Q=; h=From:To:Subject:Date:In-Reply-To:References:From; b=HZR21vmFSA6RBFN6OntCJmMyM5PF0cVV6DVe6mvpi/trvnTshoFwLMzaPjTgnWNHq rkhAOZVGlcnc0hcRn04/3jwlKRRvKm1H4Td9bE5+9MfchYEy/YZuIdY4sWRSSF+mAc y+gM3h/ePbNzG6FhO1uJtqVtJ/hSKuiq7uRGeuf33+TPZRpaOusRsMGGGbrc6H3/dV XNTjwFrSwsp2Wc9OppLwgg0kOrMWQPj40/AADwByEAkGl8FLEo2awrrch7OymCWyIc UEPKDxSKAt4sl6AoDDoS+QBMhqOwJpOjH3DzdJ8EIpj9v4Zw6Hk/J+GkHan5Jm5OhT twFnASZ90cYog== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id 7FE2EC53BD1; Thu, 14 Dec 2023 07:14:57 +0000 (UTC) From: bugzilla-daemon@kernel.org To: kvm@vger.kernel.org Subject: [Bug 218259] High latency in KVM guests Date: Thu, 14 Dec 2023 07:14:57 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: AssignedTo virtualization_kvm@kernel-bugs.osdl.org X-Bugzilla-Product: Virtualization X-Bugzilla-Component: kvm X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: kernelbugs2012@joern-heissler.de X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: virtualization_kvm@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 https://bugzilla.kernel.org/show_bug.cgi?id=3D218259 --- Comment #2 from Joern Heissler (kernelbugs2012@joern-heissler.de) --- Hi, 1. KSM is already disabled. Didn't try to enable it. 2. NUMA autobalancing was enabled on the host (value 1), not in the guest. = When disabled, I can't see the issue anymore. 3. tdp_mmu was "Y", disabling it seems to make no difference. So might be related to NUMA. On older kernels, the flag is 1 as well. There's one difference in the kernel messages that I hadn't noticed before.= The newer one prints "pci_bus 0000:7f: Unknown NUMA node; performance will be reduced" (same with ff again). The older ones don't. No idea what this mean= s, if it's important, and can't find info on the web regarding it. I think the kernel is preemptible: "uname -a" shows: "Linux vm123 6.1.0-15-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.66-1 (2023-12-09) x86_64 GNU/Linux" "grep -i" on the config shows: CONFIG_PREEMPT_BUILD=3Dy # CONFIG_PREEMPT_NONE is not set CONFIG_PREEMPT_VOLUNTARY=3Dy # CONFIG_PREEMPT is not set CONFIG_PREEMPT_COUNT=3Dy CONFIG_PREEMPTION=3Dy CONFIG_PREEMPT_DYNAMIC=3Dy CONFIG_PREEMPT_RCU=3Dy CONFIG_HAVE_PREEMPT_DYNAMIC=3Dy CONFIG_HAVE_PREEMPT_DYNAMIC_CALL=3Dy CONFIG_PREEMPT_NOTIFIERS=3Dy CONFIG_DRM_I915_PREEMPT_TIMEOUT=3D640 # CONFIG_DEBUG_PREEMPT is not set # CONFIG_PREEMPT_TRACER is not set # CONFIG_PREEMPTIRQ_DELAY_TEST is not set Attaching output of "dmesg" and "lspci -v". Perhaps there's something usefu= l in there. --=20 You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.=