From owner-svn-src-all@FreeBSD.ORG Sun Jul 11 13:04:23 2010 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A451F106566C; Sun, 11 Jul 2010 13:04:23 +0000 (UTC) (envelope-from lstewart@freebsd.org) Received: from lauren.room52.net (lauren.room52.net [210.50.193.198]) by mx1.freebsd.org (Postfix) with ESMTP id 31D548FC0C; Sun, 11 Jul 2010 13:04:23 +0000 (UTC) Received: from lawrence1.loshell.room52.net (ppp59-167-184-191.static.internode.on.net [59.167.184.191]) by lauren.room52.net (Postfix) with ESMTPSA id 278DE7E84A; Sun, 11 Jul 2010 23:04:21 +1000 (EST) Message-ID: <4C39C154.7090706@freebsd.org> Date: Sun, 11 Jul 2010 23:04:20 +1000 From: Lawrence Stewart User-Agent: Mozilla/5.0 (X11; U; FreeBSD amd64; en-AU; rv:1.9.1.10) Gecko/20100704 Thunderbird/3.0.5 MIME-Version: 1.0 To: Kostik Belousov References: <201006130239.o5D2du3m086332@svn.freebsd.org> <20100613101025.GD1320@garage.freebsd.pl> <4C158B71.205@freebsd.org> <20100614085205.GD13238@deviant.kiev.zoral.com.ua> <4C1605A7.2000202@freebsd.org> <20100614104349.GF13238@deviant.kiev.zoral.com.ua> <4C198A90.3060905@freebsd.org> <20100617071300.GX13238@deviant.kiev.zoral.com.ua> <4C1AD292.5070508@freebsd.org> <4C369172.4020700@freebsd.org> <20100711082454.GN2408@deviant.kiev.zoral.com.ua> In-Reply-To: <20100711082454.GN2408@deviant.kiev.zoral.com.ua> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r209119 - head/sys/sys X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 11 Jul 2010 13:04:23 -0000 On 07/11/10 18:24, Kostik Belousov wrote: > On Fri, Jul 09, 2010 at 01:03:14PM +1000, Lawrence Stewart wrote: >> On 06/18/10 11:57, Lawrence Stewart wrote: >>> On 06/17/10 17:13, Kostik Belousov wrote: >>>> On Thu, Jun 17, 2010 at 12:38:08PM +1000, Lawrence Stewart wrote: >>>>> On 06/14/10 20:43, Kostik Belousov wrote: >>> [snip] >>>>>> Or, you could ditch the sum at all, indeed using ({}) and returning the >>>>>> result. __typeof is your friend to select proper type of accumulator. >>>>> >>>>> So, something like this? >>>>> >>>>> #define DPCPU_SUM(n, var) __extension__ \ >>>>> ({ \ >>>>> u_int >>>>> _i; \ >>>>> __typeof((DPCPU_PTR(n))->var) >>>>> sum; \ >>>>> >>>>> \ >>>>> sum = >>>>> 0; \ >>>>> CPU_FOREACH(_i) >>>>> { \ >>>>> sum += (DPCPU_ID_PTR(_i, >>>>> n))->var; \ >>>>> >>>>> } \ >>>>> >>>>> sum; \ >>>>> }) >>>>> >>>>> Which can be used like this: >>>>> >>>>> totalss.n_in = DPCPU_SUM(ss, n_in); >> >> [snip] >> >>> I'll commit the above version of the macro this evening (GMT+10) unless >>> I hear any objections. Thanks to all of you for your input. >> >> Any objections to the following patch going in as a follow up to the >> above discussion? >> >> http://people.freebsd.org/~lstewart/patches/tcp_ffcaia2008/dpcpu_zeromember_9.x.r209745.patch >> >> Turns out I need DPCPU_ZERO to fix a bug in SIFTR and it occurred to me >> that providing variants of the macros which work on the DPCPU variable >> itself or a member of a DPCPU struct makes good sense. The new patch >> therefore renames my original DPCPU_SUM to DPCPU_MEMBERSUM and includes >> DPCPU_MEMBERZERO(). >> >> Also open to suggestions on a sensible shortening of MEMBER or other >> appropriate and descriptive indicator to reduce the macro name lengths. >> MBR implies some sort of memory barrier... any other ideas? > > I suggest changing MEMBER to VAR. I'd be happy with that. If I don't get a better suggestion or an objection I'll go with DPCPU_VARZERO and DPCPU_VARSUM. Thanks for the input. > Are the macros only believed to be useful, or you already use them ? DPCPU_ZERO and DPCPU_MEMBERSUM I have an immediate use for in the SIFTR code. I don't have an immediate use for DPCPU_MEMBERZERO and DPCPU_SUM, but I can imagine they will both find use once people start converting stats counters and various other kernel data to DPCPU. > For the usual reasons, it seems to be better to wrap DCPU_ZERO > into do/while (0). Oops, good point. Will do. Cheers, Lawrence