From owner-svn-src-head@FreeBSD.ORG Fri Dec 28 12:53:38 2012 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id CD963A12; Fri, 28 Dec 2012 12:53:38 +0000 (UTC) (envelope-from asmrookie@gmail.com) Received: from mail-la0-f48.google.com (mail-la0-f48.google.com [209.85.215.48]) by mx1.freebsd.org (Postfix) with ESMTP id B3C968FC0C; Fri, 28 Dec 2012 12:53:37 +0000 (UTC) Received: by mail-la0-f48.google.com with SMTP id ej20so738254lab.7 for ; Fri, 28 Dec 2012 04:53:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:reply-to:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; bh=gbk1fsMNZKREvvx6rHflvzsFBqIt8Qtvc68GlyGA/6Y=; b=UorYlU4A38OYCjzG4RFeb1cZNGR7YxzVZ5A2vIlr0WXDpxFfrvJmeKAmxBFFOGpYnf FHNlkeav4AlrLaJBas7wVGrDWcmvFs6hfL26RA7SIIUrl3/bN/4CBrX7SxrJFdEK0adq 6RiGwubjTI3GXh/uoiLaDhDVBwn8igxrKx8PrAJI2C1diOVRJkV72Q8Sli/DxUPGLOhE S/DbX/xw8+IlW9bf7brc0aNDu+oVT86GkIfiKb1Lc+Ww0J1CZrkUdYMEzbAu/aGWwYVl myPmT0glPsJFSRT2L72SD8jliB4EbRSw+oONY3sMCyB9F4HAYxGOfuo4kPzcIDhCvQ9f aBMQ== MIME-Version: 1.0 Received: by 10.112.14.169 with SMTP id q9mr13227042lbc.110.1356699215927; Fri, 28 Dec 2012 04:53:35 -0800 (PST) Sender: asmrookie@gmail.com Received: by 10.112.84.193 with HTTP; Fri, 28 Dec 2012 04:53:35 -0800 (PST) In-Reply-To: <20121228082038.GZ80310@FreeBSD.org> References: <201212271236.qBRCawuU078203@svn.freebsd.org> <20121227124657.GX80310@FreeBSD.org> <20121227132507.GY80310@FreeBSD.org> <20121228082038.GZ80310@FreeBSD.org> Date: Fri, 28 Dec 2012 13:53:35 +0100 X-Google-Sender-Auth: crAALthJRXjAPn4VFhmgCvXg2Uc Message-ID: Subject: Re: svn commit: r244732 - head/sys/sys From: Attilio Rao To: Gleb Smirnoff Content-Type: text/plain; charset=UTF-8 Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: attilio@FreeBSD.org List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 28 Dec 2012 12:53:38 -0000 On Fri, Dec 28, 2012 at 9:20 AM, Gleb Smirnoff wrote: > On Thu, Dec 27, 2012 at 08:37:24AM -0800, Attilio Rao wrote: > A> > Speaking of which, as you are here, I just found out that r241037 > A> > breaks the alignment of the structure. > A> > Infact the padding member is not updated accordingly. > A> > > A> > We don't have a param to control L2 caches, but I think that we can > A> > safely align them to the L1 cacheline for sure. > A> > Also, note that this padding is completely broken for MI requirements > A> > (it just assumes blindly 128 bytes L2 cachelines, which not always > A> > true even on i386). > A> > A> More specifically this patch: > A> http://www.freebsd.org/~attilio/bufring_pad.patch > A> > A> Of course I don't think the optimization is important in the > A> DEBUG_BUFRING on case, so the patch should be fine. > > Agreed, thanks. And thanks for removing the br_prod_bufs. > > Sorry for breaking alignment in r241037. > > And last time we talked about alignment, it was noticed that our > current CACHE_LINE_SIZE on amd64 is 128, while real size is 64. > This 128 was some optimisation proposed by Intel for some past > generation of CPUs and is no longer actual. Shouldn't we change it > back to 64? There was a recent thread on -arch about it. By Intel devs tests it seems that CACHE_LINE_SIZE=128 really gives a performance boost when NLM prefetcher is enabled while it doesn't hurt otherwise. Did you also rewview the second patch I sent? Thanks, Attilio -- Peace can only be achieved by understanding - A. Einstein