From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <swmike@swm.pp.se>
Received: from uplift.swm.pp.se (ipv6.swm.pp.se [IPv6:2a00:801::f])
 (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits))
 (No client certificate requested)
 by lists.bufferbloat.net (Postfix) with ESMTPS id B65C73B2A4
 for <bloat@lists.bufferbloat.net>; Fri,  4 Sep 2020 09:41:07 -0400 (EDT)
Received: by uplift.swm.pp.se (Postfix, from userid 501)
 id D5779B1; Fri,  4 Sep 2020 15:41:06 +0200 (CEST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=swm.pp.se; s=mail;
 t=1599226866; bh=+GO8NHTkUrGvpUS7CfHJNvVBLTrTn1FN2VaFnWe1b3g=;
 h=Date:From:To:cc:Subject:In-Reply-To:References:From;
 b=N5Nsnc8Z4D7h407IbC321dyKH395BLS1m174ok3CCoYnD28K1I9pq9zheQ8jblQ1M
 ISDv1+nfT9HfG+ZSCSP6498R13GmuyhlsWc5L6UWaxi3by1866Ot5TRAz6rRmpc7sZ
 un7+Cu/YJgSaF5REJpcVKv9n2IIMq0vaHL6KUsjA=
Received: from localhost (localhost [127.0.0.1])
 by uplift.swm.pp.se (Postfix) with ESMTP id D2529B0;
 Fri,  4 Sep 2020 15:41:06 +0200 (CEST)
Date: Fri, 4 Sep 2020 15:41:06 +0200 (CEST)
From: Mikael Abrahamsson <swmike@swm.pp.se>
To: Jonathan Morton <chromatix99@gmail.com>
cc: davecb@spamcop.net, bloat@lists.bufferbloat.net
In-Reply-To: <8AA690BF-B027-420B-81B1-8E9F445D5BB7@gmail.com>
Message-ID: <alpine.DEB.2.20.2009041540230.20021@uplift.swm.pp.se>
References: <alpine.DEB.2.20.2008301921450.11025@uplift.swm.pp.se>
 <87mu2bjbf8.fsf@toke.dk>
 <5DBFB383-13E8-4587-BE49-1767471D7D59@jonathanfoulkes.com>
 <87r1rliiiw.fsf@toke.dk>
 <07CD4278-D448-49D2-AC73-9C230EC041DE@jonathanfoulkes.com>
 <87imcxi4mq.fsf@toke.dk>
 <alpine.DEB.2.20.2009031512170.20021@uplift.swm.pp.se>
 <CAH8sseTmFM0xiHqg_EyD-3bPaCFCfsFOkM4HB8-XtOL0YZQr7g@mail.gmail.com>
 <877dtbgcc6.fsf@toke.dk> <8c4212c4-3acb-6616-d9a2-6bef7e65bbad@rogers.com>
 <8AA690BF-B027-420B-81B1-8E9F445D5BB7@gmail.com>
User-Agent: Alpine 2.20 (DEB 67 2015-01-07)
Organization: People's Front Against WWW
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII; format=flowed
Subject: Re: [Bloat] Other CAKE territory (was: CAKE in openwrt high CPU)
X-BeenThere: bloat@lists.bufferbloat.net
X-Mailman-Version: 2.1.20
Precedence: list
List-Id: General list for discussing Bufferbloat <bloat.lists.bufferbloat.net>
List-Unsubscribe: <https://lists.bufferbloat.net/options/bloat>,
 <mailto:bloat-request@lists.bufferbloat.net?subject=unsubscribe>
List-Archive: <https://lists.bufferbloat.net/pipermail/bloat>
List-Post: <mailto:bloat@lists.bufferbloat.net>
List-Help: <mailto:bloat-request@lists.bufferbloat.net?subject=help>
List-Subscribe: <https://lists.bufferbloat.net/listinfo/bloat>,
 <mailto:bloat-request@lists.bufferbloat.net?subject=subscribe>
X-List-Received-Date: Fri, 04 Sep 2020 13:41:07 -0000

On Fri, 4 Sep 2020, Jonathan Morton wrote:

> We're usually seeing problems with the smaller-scale CPUs found in CPE 
> SoCs, which are very much geared to take advantage of hardware 
> accelerated packet forwarding.  I think in some cases there might 
> actually be insufficient internal I/O bandwidth to get 1Gbps out of the 
> NIC, into the CPU, and back out to the NIC again, only through the 
> dedicated forwarding path.  That could manifest itself as a lot of 
> kernel time spent waiting for the hardware, and can only really be 
> solved by redesigning the hardware.

There are lots of SoCs where CPU routing results in ~100 megabit/s of 
throughput, whilst the HW offload engine is perfectly capable of full gig 
speeds. MT7621 being one that actually is supported in OpenWrt.

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se