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[2604:1380:4601:e00::3]) by mx.google.com with ESMTPS id fi7-20020a056402550700b005593aa5dc6dsi4835917edb.241.2024.01.30.12.58.33 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Jan 2024 12:58:33 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-45303-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=Bnt6HHBr; arc=pass (i=1 dkim=pass dkdomain=kernel.org); spf=pass (google.com: domain of linux-kernel+bounces-45303-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) smtp.mailfrom="linux-kernel+bounces-45303-linux.lists.archive=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by am.mirrors.kernel.org (Postfix) with ESMTPS id 6B0651F2555F for ; Tue, 30 Jan 2024 20:58:33 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E447671B58; Tue, 30 Jan 2024 20:58:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Bnt6HHBr" 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 12FB06E2AA; Tue, 30 Jan 2024 20:58:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706648304; cv=none; b=GnZzj2kJju1vYclrOdHMzbjEYWgPCrc5QfDwIvctujB6E7qXet9+HvgMOKI+7ht+tbQYhkWv9w8fUUseVz74xGdyOmZtG8bLFFkmE68Ht/EUgehVuf52lGtsStKBGHbK/MaSUVuKRndEwIp4Tz17mlDdb4TcFcargAFDtPhfdII= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706648304; c=relaxed/simple; bh=9UZiNX1ogTG54dY4oqALo68Do/m+ZrjV3ORgvb9uQPQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=oNM47rFg/rqg2gvVzf4cTOsMycXYsOAg7AohW/eHjURs5sg9zFB+mfm58Wvr1d4knb9bgkpyO00tl7OAKUNHVX9JBZ/kj1ROE14ibPL1Q+7K4WW0Nb44TjZu7HVVe9Mb3qlSGkOujmd97IJVXPJpdLLOBYVy6PoQmJJuk1aNFZ0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Bnt6HHBr; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4885BC433C7; Tue, 30 Jan 2024 20:58:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706648303; bh=9UZiNX1ogTG54dY4oqALo68Do/m+ZrjV3ORgvb9uQPQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Bnt6HHBr3uaRcd2uD017LUys7iMuT7ppaB00f9hdAngoF+PngNrGy2AZGWc4KiJ6M PBmjVSlO+FUFdM//y2hJUS/OjO+CgnAbrjfURH1vc0DQStBxRgTtIHL+i/NV3KFgvO /XNIgarGOXDR9U1ts/51mq5hGn9A699RDjsXG4U6QzFAzKvQ49ZxYzsI5PorYykCma qKbQp9mfDEU+a7C+r/yVYhe4TTWfuVkdsXen7Bi/xdyAN3D55L11ewcyTINZ+OuGV/ O7fqlGp0t8aWK1AOq7WMLOl/leM5AyokOshYcD8BtINCxYZO7Jqid+bW4XQXDIfSIf MyrEq0xvnsRaw== Date: Tue, 30 Jan 2024 15:58:21 -0500 From: Sasha Levin To: Pavel Machek Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, "Borislav Petkov (AMD)" , tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com, x86@kernel.org, puwen@hygon.cn, seanjc@google.com, kim.phillips@amd.com, reinette.chatre@intel.com, babu.moger@amd.com, jmattson@google.com, peterz@infradead.org, ashok.raj@intel.com, rick.p.edgecombe@intel.com, brgerst@gmail.com, mjguzik@gmail.com, jpoimboe@kernel.org, nik.borisov@suse.com, aik@amd.com, vegard.nossum@oracle.com, daniel.sneddon@linux.intel.com, acdunlap@google.com Subject: Re: [PATCH AUTOSEL 5.10 09/10] x86/barrier: Do not serialize MSR accesses on AMD Message-ID: References: <20240115232818.210010-1-sashal@kernel.org> <20240115232818.210010-9-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: On Tue, Jan 16, 2024 at 09:44:01PM +0100, Pavel Machek wrote: >Hi! > >> From: "Borislav Petkov (AMD)" >> >> [ Upstream commit 04c3024560d3a14acd18d0a51a1d0a89d29b7eb5 ] >> >> AMD does not have the requirement for a synchronization barrier when >> acccessing a certain group of MSRs. Do not incur that unnecessary >> penalty there. >... >> Performance captured using an unmodified ipi-bench using the 'mesh-ipi' option >> with and without weak_wrmsr_fence() on a Zen4 system also showed significant >> performance improvement without weak_wrmsr_fence(). The 'mesh-ipi' option ignores >> CCX or CCD and just picks random vCPU. >> >> Average throughput (10 iterations) with weak_wrmsr_fence(), >> Cumulative throughput: 4933374 IPI/s >> >> Average throughput (10 iterations) without weak_wrmsr_fence(), >> Cumulative throughput: 6355156 IPI/s >> >> [1] https://github.com/bytedance/kvm-utils/tree/master/microbenchmark/ipi-bench > >Speed improvement, not a bugfix. Please drop. Dropped, thanks! -- Thanks, Sasha