From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754929AbaEFUSE (ORCPT ); Tue, 6 May 2014 16:18:04 -0400 Received: from mail-pa0-f47.google.com ([209.85.220.47]:65247 "EHLO mail-pa0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751664AbaEFUSB (ORCPT ); Tue, 6 May 2014 16:18:01 -0400 Message-ID: <1399407478.15399.81.camel@edumazet-glaptop2.roam.corp.google.com> Subject: Re: [PATCH 08/24] net, diet: Make TCP metrics optional From: Eric Dumazet To: Andi Kleen Cc: josh@joshtriplett.org, David Miller , andi@firstfloor.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, tom.zanussi@linux.intel.com Date: Tue, 06 May 2014 13:17:58 -0700 In-Reply-To: <20140506183216.GM19657@tassilo.jf.intel.com> References: <1399328773-6531-9-git-send-email-andi@firstfloor.org> <20140505.231229.136734008603421707.davem@davemloft.net> <20140506032114.GP2382@two.firstfloor.org> <20140505.232327.578134514220748085.davem@davemloft.net> <20140506155703.GA20391@cloud> <1399394359.15399.20.camel@edumazet-glaptop2.roam.corp.google.com> <20140506183216.GM19657@tassilo.jf.intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2014-05-06 at 11:32 -0700, Andi Kleen wrote: > > We simply can not compete with user space, as a programmer is free to > > keep what he really wants/needs. > > Not true. You can shake the kernel as much as you want, you wont make : - a TCP socket - a dentry - an inode - a file structure - eventpoll structures (assuming epoll use) - 2 dst per flow. In 1024 bytes of memory, and keep an efficient kernel to handle arbitrary number of sockets using the venerable and slow BSD socket api. I was objecting to the "crazy things like LWIP" comment from Josh, not to your patches in general. I actually took a look at them but stopped at patch 22 Adding ~1000 lines of code to save few KB was the point I gave up.