From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DACB3C54EE9 for ; Wed, 7 Sep 2022 16:31:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=wl2jbLwFCLG9Syeebq0hFEpHT1sVFT5dW55015sYv5s=; b=LEd/tY0QbAlN10 xAb6fZfmib6df5M5jxir318WcCsL7GYljoDaKsK8+733WaPIEqw0IAkBiRIfXip4RqvqlECt+XcVk t6ma/EszEhLFp6F3qsIZB6pOinSqRcYJwHjVCUPdPRWUhzqPPLBmphFF5LJAzKiBqm+KlvMBFoFPb fxGSj0x7ZhXUD3pq7/W0J0Wa4MbbXhkDBkxmvKe9rjvCqOF8zvLs/Hh/lR+VCNi5XNY746d/TwOyk LzXauktiI0cDS23d11CxifF43jvjo2fbzt22336aOUaUn6mKb6gM0sJXm9ZQkQvv4k8MhV3Zy6qfA DaKgsPg3xUbhIy5G5UPg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oVxwE-007mH7-Ds; Wed, 07 Sep 2022 16:30:06 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oVxwA-007mDg-Q3 for linux-arm-kernel@lists.infradead.org; Wed, 07 Sep 2022 16:30:04 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 42F1861300; Wed, 7 Sep 2022 16:29:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 992B2C433D6; Wed, 7 Sep 2022 16:29:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1662568198; bh=SyUuqxI7aO6x27tKuLX1Jvc84+ethL9Y8ImhuZD72ic=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=auXUv95Dz+XmRyZv0gH7xXUZMUC5dFxAfKSbn2MrZeUjZTAZWREFVpE9x9DjWE19f jIx+0VPR4QR9t1Z4ec8j9SMHtrDwD+4UFTw54M+Y4z0Hp+W7haOdbBZ64RjNpdmH7x 10tJgw/DU5WqK6Rvn620RNhoBnwSZxMndP/tzcVwPxDnPQ4d9MYx+YLWEfD+DrTsw3 sELqOvem6CILw35y8gpw/7507lfTTowCGO7RPZYiWzAxWhEx+weeNvpcZ3PWyQqY4a WJ3In5P+GF0b+oMPy+7Y/uhHftwps/TfkEQiW6aRTkVi97zslovShUeS8q4fAvU4B5 t/m6rkA3CNGZg== Date: Wed, 7 Sep 2022 17:29:53 +0100 From: Will Deacon To: Catalin Marinas Cc: Liu Song , james.morse@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] arm64: spectre: increase parameters that can be used to turn off bhb mitigation individually Message-ID: <20220907162952.GC30558@willie-the-truck> References: <1661514050-22263-1-git-send-email-liusong@linux.alibaba.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220907_093002_909710_39DBAA05 X-CRM114-Status: GOOD ( 17.60 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Sep 07, 2022 at 03:29:05PM +0100, Catalin Marinas wrote: > On Fri, Aug 26, 2022 at 07:40:50PM +0800, Liu Song wrote: > > From: Liu Song > > > > In our environment, it was found that the mitigation BHB has a great > > impact on the benchmark performance. For example, in the lmbench test, > > the "process fork && exit" test performance drops by 20%. > > So it is necessary to have the ability to turn off the mitigation > > individually through cmdline, thus avoiding having to compile the > > kernel by adjusting the config. > > > > Signed-off-by: Liu Song > > If people want to disable this mitigation and know what they are doing, > I have no objection: > > Acked-by: Catalin Marinas Thanks! > (I guess that's more like 6.1 material) Yup, agreed. I take it you'll pick it up, then? Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel