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 001A4C54EE9 for ; Wed, 7 Sep 2022 14:31:32 +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=ToiiyTkZyKGEaJfjmupbISpumTEK7vRGGRexbXuM17k=; b=riBEakbOEbQtzv sRIVfo707WRPpVNYpn71B8kCojTgcsiuzpGOkycvj5bUg0x7Hie1igmju9tTV4Ij+DBpPcdwec+Dh wN69XjOpYR/EJHxq/e86dlSGkOxHF4NowFTx1EJEgPvhyUaLEBP1AstQjDqKy6hRt1uSdWKzf6hUn 4nACm7sD8fP21GDkV9Rl7G8D0eDWlFXJNuxQ3NccQerLJipDlxCLnnPfM0mcdRgrRLzedT/X1MV0o DkrPzvwDfo1+mg621l4ck2ad0QC7V1yqW+wHWsWJ4AKwMlttSaoFVV3x/gN+I1dCcMygnu+Pk8gJ3 tGlHA4c1plIknyOnVlPQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oVw4J-006u8O-HY; Wed, 07 Sep 2022 14:30:19 +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 1oVw3C-006tHl-Ni for linux-arm-kernel@lists.infradead.org; Wed, 07 Sep 2022 14:29:12 +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 39B426192E; Wed, 7 Sep 2022 14:29:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96623C433D6; Wed, 7 Sep 2022 14:29:08 +0000 (UTC) Date: Wed, 7 Sep 2022 15:29:05 +0100 From: Catalin Marinas To: Liu Song Cc: will@kernel.org, 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: References: <1661514050-22263-1-git-send-email-liusong@linux.alibaba.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1661514050-22263-1-git-send-email-liusong@linux.alibaba.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220907_072910_854287_2C0B3147 X-CRM114-Status: GOOD ( 13.11 ) 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 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 (I guess that's more like 6.1 material) -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel