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=-5.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 D3934C55178 for ; Thu, 5 Nov 2020 17:02:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7606620936 for ; Thu, 5 Nov 2020 17:02:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="py845HUD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731573AbgKERCJ (ORCPT ); Thu, 5 Nov 2020 12:02:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726801AbgKERCI (ORCPT ); Thu, 5 Nov 2020 12:02:08 -0500 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0B3AC0613D2; Thu, 5 Nov 2020 09:02:08 -0800 (PST) Received: by mail-pf1-x444.google.com with SMTP id g7so1557317pfc.2; Thu, 05 Nov 2020 09:02:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=1E/GdSgvT+IfKnf/MQnxEpHIqbogE7oTSfYMSoG+muE=; b=py845HUDSn6lrlHMzWWLdBEnBIvv7pnBrtqYEs7F4lClin5wEfNwRsfuebyIhBrs0F yq9wBocpigv9ECrczLtxDjmUTDnMWAR786Vx64Yy2bcRd0gtj84/iWFHKTy+ijgW6ZI1 JrcddhmYxQlPyOV178ghPINfaS/SzV9Vuwt8T6XlEebjsecz8PGvI7iD1VNlX4P+4uuC P1j2qqd4+L1rJYPT+AXVskMPbQcW4lV5iyF2Id5QoygLx+5h7zkId0VSLBUnQMktUKfZ GLYoVbrP/pRMAb9Re49tHlMWnwh+TOtzdxMIKpFx0kLjncq1PXFKQ0CrwtQk0GLv4zXz C98g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=1E/GdSgvT+IfKnf/MQnxEpHIqbogE7oTSfYMSoG+muE=; b=bwNLdkqwi3/NqTcZP8wNee9n4NxMH7f8WR4l+kC9/pmtN6zso9gze3gclLnsipH0tX aGbcPGepBwhM7i/F8owT4WfR8gfY7ujq5jnt4btE+gTBSgQFzEO5Vtis3ahLidJSt1LT eFL58stUqIouQSP7jGdkkm+h3Iijyd6zVWZ9yTiS9/OoG8dZfEHw0DvWV15Rp6w9K/Jh cDyq9LUDhlkH4cXXToKQr4PPMjoBKt94Di4vqkio95BHSX6QOvPVzeLuXak97JE7quyM aT8AKxfe/Mc8U0UrZnwB7feD9ywsLL1rwNXljZe2EBCnH7zeSnUXfV4VljGgljLKdpQ5 S5bg== X-Gm-Message-State: AOAM531umHwoDEw9vuhYffAT0rx94wWRozMpvdLAD+h2GuGVbLaXEiZP clImbAGLsKNS/m3rZYmoORg= X-Google-Smtp-Source: ABdhPJwbvoK5kkf0kxlXbmOFQ64ONheTWuD39VvDwGzob7HSOf95ha2r81Of2Bb41jZos3/aE9Ds2w== X-Received: by 2002:a65:67c2:: with SMTP id b2mr3214406pgs.39.1604595728164; Thu, 05 Nov 2020 09:02:08 -0800 (PST) Received: from hoboy.vegasvil.org (c-73-241-114-122.hsd1.ca.comcast.net. [73.241.114.122]) by smtp.gmail.com with ESMTPSA id f21sm2970903pga.32.2020.11.05.09.02.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Nov 2020 09:02:07 -0800 (PST) Date: Thu, 5 Nov 2020 09:02:04 -0800 From: Richard Cochran To: Vladimir Oltean Cc: min.li.xe@renesas.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next 3/3] ptp: idt82p33: optimize _idt82p33_adjfine Message-ID: <20201105170204.GA5258@hoboy.vegasvil.org> References: <1604505709-5483-1-git-send-email-min.li.xe@renesas.com> <1604505709-5483-3-git-send-email-min.li.xe@renesas.com> <20201104164657.GE16105@hoboy.vegasvil.org> <20201105003556.tpgvlh3ponyxzjjl@skbuf> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201105003556.tpgvlh3ponyxzjjl@skbuf> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 05, 2020 at 02:35:56AM +0200, Vladimir Oltean wrote: > On the other hand and with all due respect, saying that it may have been > 'buggy on some archs back in the day' and then not bringing any evidence > is a bit of a strange claim to make. You're right. I made the effort to look back into the days of v3.0, and the only thing I could find is that the 32 bit implementation of div_s64 does extra operations and invokes an additional function call. But the difference in performance, if any, is probably not very large. > I am actively using div_s64 in drivers/net/dsa/sja1105/sja1105_ptp.c > successfully on arm and arm64. Yeah, I see div_s64 has found its way into the ntp code, too, so it must be fine. Thanks, Richard