From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-x233.google.com (mail-lf0-x233.google.com [IPv6:2a00:1450:4010:c07::233]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id B7F343B2BC for ; Thu, 23 Jun 2016 22:37:09 -0400 (EDT) Received: by mail-lf0-x233.google.com with SMTP id q132so107262664lfe.3 for ; Thu, 23 Jun 2016 19:37:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=RokpHN+JyGaZ8vOO9YGeN+g9xNtK9EGPUcIJzYplGZs=; b=T7R+vAhffo6V6+CU4CshButWQbI21AffOTn00IGUTbSdFXFTOp3Ytv+0X+e0CgIWXZ TG/fAX4G26EPucDtMASdy3B5qR4tQzHb2u0emDHNt+nG0rGx6dj2mcW/YU1RosEIbA9f xWXMnEqd3eX+9KmUoyJt9hp+zyqZf6Xszd+CmIoTtZn4Ym7DJp0+3ABVbJLgOq5l3OeN /MLkoIO2fDXMxcutYtgZhKYLmevfjSlfMRDmw4a+Wasxp3T8ZZhlce56O1hecs2vu49d VSCe8hIEY+S6ICXK1tFYCWvoH3vhQo3lgS/7wHqMA8BKaBMdOdC64YiHCIciHo1gfzJ1 OwRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=RokpHN+JyGaZ8vOO9YGeN+g9xNtK9EGPUcIJzYplGZs=; b=XgoCsy4+UgzdtRWRDNFyvrn/w/+FTyRnRp2MwXr5XpPbwwcNZZNoqKAz1pg0zqlEH8 KjBMjwRINIA3AfPvvbdNORHaN0XAKrzvoNWBppSm+2dxDBNGfhQRrsfuMfw3ubT/TZKF mrX2Hn3EFDlKdH0RjDQuqjifkE9TZn+q77zvvSBCXMifrkd2q2vK81B4Qc9DLEVqGc5a pjJyGAHP1aUrJic2bxMgM3vHoOECd2TS5fmGezi4Du3BW2nioiz4G8TBvcqkZgzmEhM7 l/zTIO9LGEKJXQHs2OWJu87IwmGysD9kUoNto7i+IOFuFTTqV914KBzSoM7ZMAl56tPY 3xQw== X-Gm-Message-State: ALyK8tIQpnvBeqxHCaJ7sZAZAuHbouLKCE5p65/cnq4zevbfn8dxCXCFxE3Bdu8WYD2/CQ== X-Received: by 10.25.219.27 with SMTP id s27mr518894lfg.129.1466735828515; Thu, 23 Jun 2016 19:37:08 -0700 (PDT) Received: from bass.home.chromatix.fi (37-33-96-207.bb.dnainternet.fi. [37.33.96.207]) by smtp.gmail.com with ESMTPSA id q4sm572216lfd.27.2016.06.23.19.37.07 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 23 Jun 2016 19:37:07 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) From: Jonathan Morton In-Reply-To: <87mvmbpi7d.wl-jch@pps.univ-paris-diderot.fr> Date: Fri, 24 Jun 2016 05:37:05 +0300 Cc: Dave Taht , "babel-users@lists.alioth.debian.org" , "cerowrt-devel@lists.bufferbloat.net" Content-Transfer-Encoding: quoted-printable Message-Id: <0173B4D2-C84A-4200-B388-F8E964CAEB86@gmail.com> References: <87lh1xihnv.wl-jch@pps.univ-paris-diderot.fr> <87vb0zpnel.wl-jch@pps.univ-paris-diderot.fr> <87oa6rpl7h.wl-jch@pps.univ-paris-diderot.fr> <87mvmbpi7d.wl-jch@pps.univ-paris-diderot.fr> To: Juliusz Chroboczek X-Mailer: Apple Mail (2.3124) Subject: Re: [Cerowrt-devel] Why we are discussing ARM [was: Cross-compiling to armhf] X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Jun 2016 02:37:10 -0000 > On 24 Jun, 2016, at 03:02, Juliusz Chroboczek = wrote: >=20 > Raspberry Pi: doesn't run armhf userspace, no wifi, eth connected by = USB; > Raspberry Pi v2/v3: requires binary blobs, wifi and eth connected = over USB; Actually, the only substantial difference between the first R-Pi and the = second is one ARM1176JZF-S core (ARMv6 with an FPU) versus four = Cortex-A7s (ARMv7-A with FPU and SIMD). They can both run armhf userspace, as we were just discussing, and they = can both have external wifi attached via USB. What the first version = *can=E2=80=99t* do is run ARMv7 code - which isn=E2=80=99t very much of = a difference, honestly. There is a big performance jump though. The third, current version gets four Cortex-A53s (which support AArch64 = as well as 32-bit code) and includes a built-in wifi radio attached via = SDIO. Otherwise, it=E2=80=99s identical to the second version. I = haven=E2=80=99t got one of these yet. I=E2=80=99m told that all the = official R-Pi distros remain 32-bit for compatibility with the older = versions, but that=E2=80=99s not a concern if you=E2=80=99re rolling = your own. They also *all* require a binary blob to bootstrap the chip. Apparently = Broadcom=E2=80=99s SoC architecture puts the GPU - which occupies the = lion=E2=80=99s share of the die area - in charge of boot, with the CPU = subordinate. In fact the original R-Pi=E2=80=99s chip was designed as = an independent embedded-class GPU, with its ARM core provided as a mere = command translator! Needless to say, the GPU hardware goes woefully = underutilised, but is retained in the newer versions to preserve = compatibility. I agree however that none of the R-Pis make good routers at the = performance levels we want. They just don=E2=80=99t have the right kind = of I/O: we need direct or PCIe attachment of Ethernet and wifi MACs, not = USB and SDIO. - Jonathan Morton