From mboxrd@z Thu Jan 1 00:00:00 1970 From: josh@joshtriplett.org Subject: Re: [PATCH 08/24] net, diet: Make TCP metrics optional Date: Tue, 6 May 2014 09:41:08 -0700 Message-ID: <20140506164108.GA20536@cloud> References: <20140506032114.GP2382@two.firstfloor.org> <20140505.232327.578134514220748085.davem@davemloft.net> <20140506155703.GA20391@cloud> <20140506.115941.428706504757835279.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: andi@firstfloor.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, tom.zanussi@linux.intel.com, ak@linux.intel.com To: David Miller Return-path: Received: from relay3-d.mail.gandi.net ([217.70.183.195]:46158 "EHLO relay3-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751747AbaEFQlN (ORCPT ); Tue, 6 May 2014 12:41:13 -0400 Content-Disposition: inline In-Reply-To: <20140506.115941.428706504757835279.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, May 06, 2014 at 11:59:41AM -0400, David Miller wrote: > From: josh@joshtriplett.org > Date: Tue, 6 May 2014 08:57:03 -0700 > > > On Mon, May 05, 2014 at 11:23:27PM -0400, David Miller wrote: > >> From: Andi Kleen > >> Date: Tue, 6 May 2014 05:21:14 +0200 > >> > >> > What parts would you remove to get the foot print down for a 2MB > >> > single purpose machine? > >> > >> I wouldn't use Linux, end of story. > >> > >> Maybe two decades ago, but not now, those days are over. > > > > That's a self-fulfilling prophecy: > > Making 2MB RAM machines today makes no sense at all. > > The lowest end dirt cheap smartphone, something which fits on > someone's pocket, has gigabytes of ram. The lowest-end smartphone isn't anywhere close to "dirt cheap", and hardly counts as "embedded" at all anymore. Smartphones cost $100+; we're talking about systems in the low tens of dollars or less. These systems will have no graphics, no peripherals, and only one or two specific functions. The entirety of their functionality will likely consist of a single userspace program; they might not even have a PID 2. *That's* the kind of "embedded" we're talking about, not the supercomputers we carry around in our pockets. Every KB of RAM costs real money and SoC die area (for eDRAM/eSRAM). Look at how much cache low-end processors have, and imagine running entirely out of *that*. Let's not surrender that entire class of devices to VxWorks, FreeRTOS, and other painfully non-Linux systems, when we already know it's possible to run Linux on them successfully. - Josh Triplett