From owner-freebsd-net@FreeBSD.ORG Sat May 17 14:52:29 2014 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id E275F304 for ; Sat, 17 May 2014 14:52:29 +0000 (UTC) Received: from mail-qc0-x22f.google.com (mail-qc0-x22f.google.com [IPv6:2607:f8b0:400d:c01::22f]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id A2B632A19 for ; Sat, 17 May 2014 14:52:29 +0000 (UTC) Received: by mail-qc0-f175.google.com with SMTP id w7so6319990qcr.34 for ; Sat, 17 May 2014 07:52:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type:content-transfer-encoding; bh=CnKzEtxzU0L9vrZ04elOL6rYhwkxXwQAz1TD8A4we1g=; b=wKJLz0t7bcmc9CH+X5Vr6qb3esmagB7rAEKjs7+F5B4IG3Kq7uolyRnbQUKXej3moy mTvHaeA2Xgn6EQziZ1ZwzHvc2kq+VyYxf3RAo+CHJlvo5JP29RhgXgeRPES0cFnAotpu Wllrqrjttvv3VE/k+ybFSvDxdjPPOSNZ+WFW2JxYqw4jmcO1F7m38ycGPV/kjGK0o30c q33avZE8aBV8GqTykhFEQvVIUHbQcNnSXdfvXzs3ongnxDf80QYOUsRVNmFspW3uswKX +pAFmg/kURMUN/p+CJJWWUdBFcVP8/EeZ8ek3wlvS+fmgqTTHEk/+aNHOYcg7NO+KE8p FXzw== MIME-Version: 1.0 X-Received: by 10.224.37.10 with SMTP id v10mr28438397qad.98.1400338348530; Sat, 17 May 2014 07:52:28 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.224.191.201 with HTTP; Sat, 17 May 2014 07:52:28 -0700 (PDT) In-Reply-To: References: <080FBD5B7A09F845842100A6DE79623346F2EB44@BRN1WNEXMBX01.vcorp.ad.vrsn.com> Date: Sat, 17 May 2014 07:52:28 -0700 X-Google-Sender-Auth: Rwvjp_npmufsaWci2ekNI5wApJE Message-ID: Subject: Re: [rfc] tcp timer update for RSS From: Adrian Chadd To: "Bentkofsky, Michael" Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: "freebsd-net@freebsd.org" X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 17 May 2014 14:52:30 -0000 .. and as a note - it'll all be behind #ifdef RSS. -a On 17 May 2014 07:49, Adrian Chadd wrote: > On 17 May 2014 07:44, Bentkofsky, Michael wrot= e: >> Hi Adrian, >> >> >> >> I haven=E2=80=99t had the chance to look this over carefully yet as we= =E2=80=99re at BSDCan. >> I think I understand what you=E2=80=99re trying to achieve by aligning t= he per-CPU >> timer processing per core. In principal that sounds reasonable, although= I >> am unsure if you were trying to solve a particular performance issue wit= h >> this particular change. My sense is this is all preparatory with the goa= l of >> all inp processing to become per core. Could you comment on the general >> evolution you=E2=80=99re considering? Do most of the PCB structures beco= me per-core, >> as in PCB groups? >> >> >> >> If you=E2=80=99d like us to test this change, I=E2=80=99m happy to do so= . At the moment I >> don=E2=80=99t know if we=E2=80=99d expect to see any benefit =E2=80=93 d= o you have any traffic >> conditions for which this showed any difference? But we can certainly dr= ive >> many hundreds of thousands of connections at reasonably high connection >> rates if that will help. > > Hi! > > Yes, the aim is to provide RSS support in the RSS model of "align > everything to a specific core." The goal for RSS is to remove both > lock contention between cores and keep data CPU/cache local to improve > efficiency there. > > There's nothing obvious that'll be beneficial right now. The items at > https://wiki.freebsd.org/NetworkRSS have to occur before it is > beneficial to anyone. > > > > -a