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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73809C4332D for ; Fri, 20 Mar 2020 15:33:37 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2CFED2070A for ; Fri, 20 Mar 2020 15:33:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2CFED2070A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48kSV660z0zDrnR for ; Sat, 21 Mar 2020 02:33:34 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=permerror (SPF Permanent Error: Unknown mechanism found: ip:192.40.192.88/32) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by lists.ozlabs.org (Postfix) with ESMTP id 48kSMS0FKWzF0PZ for ; Sat, 21 Mar 2020 02:27:47 +1100 (AEDT) Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 02KFReLt016151; Fri, 20 Mar 2020 10:27:40 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 02KFReSa016150; Fri, 20 Mar 2020 10:27:40 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Fri, 20 Mar 2020 10:27:40 -0500 From: Segher Boessenkool To: "Aneesh Kumar K.V" Subject: Re: [PATCH] arch/powerpc/64: Avoid isync in flush_dcache_range Message-ID: <20200320152740.GG22482@gate.crashing.org> References: <20200320103242.229223-1-aneesh.kumar@linux.ibm.com> <20200320150539.GF22482@gate.crashing.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, Mar 20, 2020 at 08:38:42PM +0530, Aneesh Kumar K.V wrote: > On 3/20/20 8:35 PM, Segher Boessenkool wrote: > >On Fri, Mar 20, 2020 at 04:02:42PM +0530, Aneesh Kumar K.V wrote: > >>As per ISA and isync is only needed on instruction cache > >>block invalidate. Remove the same from dcache invalidate. > > > >Is that true on older CPUs? > > > > That is what I found by checking with hardware team. Oh, the comment right before this function says "does not invalidat the corresponding insncache blocks", so this looks fine, sorry for not looking closely enough before. > One thing i was not > able to get full confirmation about was the usage of 'sync' before 'dcbf'. Yeah, this looks like something that would matter on some implementations. Would it make anything measurably faster if you would remove that sync? Segher