Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933562Ab2EWPuM (ORCPT ); Wed, 23 May 2012 11:50:12 -0400 Received: from mail-wg0-f44.google.com ([74.125.82.44]:36326 "EHLO mail-wg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753360Ab2EWPuJ (ORCPT ); Wed, 23 May 2012 11:50:09 -0400 Date: Wed, 23 May 2012 17:50:03 +0200 From: Ingo Molnar To: Joe Perches Cc: Chen , Peter Zijlstra , Vincent Guittot , torvalds@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: Plumbers: Tweaking scheduler policy micro-conf RFP Message-ID: <20120523155003.GA8202@gmail.com> References: <1337086834.27020.162.camel@laptop> <1337096141.27694.82.camel@twins> <1337193010.27694.146.camel@twins> <1337468148.573.139.camel@twins> <20120523150359.GB26974@gmail.com> <1337787838.1734.15.camel@joe2Laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1337787838.1734.15.camel@joe2Laptop> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2097 Lines: 64 * Joe Perches wrote: > On Wed, 2012-05-23 at 17:03 +0200, Ingo Molnar wrote: > > * Chen wrote: > > > > > Still you are just trying to said that your code is not bloated? > > > Up to over 500K for a cpu scheduler. Laughing > > > > Where did you get that 500K from? You are off from the truth > > almost by an order of magnitude. > > > > Here's the scheduler size on Linus's latest tree, on 64-bit > > defconfig's: > > > > $ size kernel/sched/built-in.o > > text data bss dec hex filename > > 83611 10404 2524 96539 1791b kernel/sched/built-in.o > > > > That's SMP+NUMA, i.e. everything included. > > > > The !NUMA !SMP UP scheduler, if you are on a size starved > > ultra-embedded device, is even smaller, just 22K: > > > > $ size kernel/sched/built-in.o > > text data bss dec hex filename > > 19882 2218 148 22248 56e8 kernel/sched/built-in.o > > Here's an allyesconfig x86-32 allyesconfig includes a whole lot of debugging code so it's a pretty meaningless size test. > $ size kernel/sched/built-in.o > text data bss dec hex filename > 213892 10856 65832 290580 46f14 kernel/sched/built-in.o > > But that's not the only sched related code. > > In a 1000 cpu config, there also an extra 500+ bytes per cpu > in printk (I don't think that's particularly important btw) A 1000 cpu piece of hardware will have a terabyte of RAM or more. 0.5K per CPU is reasonable. > kernel/printk.c adds: > > static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf); > > Maybe #ifdefing this when !CONFIG_PRINTK would reduce size > a little in a few cases. I've attached a trivial suggested patch. That might make sense for the ultra-embedded. Still 500K is an obviously nonsensical number. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/