From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752466AbZBRJPm (ORCPT ); Wed, 18 Feb 2009 04:15:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751615AbZBRJPZ (ORCPT ); Wed, 18 Feb 2009 04:15:25 -0500 Received: from mail-ew0-f31.google.com ([209.85.219.31]:52110 "EHLO mail-ew0-f31.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751504AbZBRJPY (ORCPT ); Wed, 18 Feb 2009 04:15:24 -0500 MIME-Version: 1.0 In-Reply-To: <200902181528.29697.rusty@rustcorp.com.au> References: <1234722028-8110-1-git-send-email-andr345@gmail.com> <200902181528.29697.rusty@rustcorp.com.au> Date: Wed, 18 Feb 2009 10:15:21 +0100 Message-ID: Subject: Re: [RFC PATCH 0/6] module, kbuild: Faster boot with custom kernel. From: Kay Sievers To: Rusty Russell Cc: Andreas Robinson , sam@ravnborg.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 18, 2009 at 05:58, Rusty Russell wrote: > On Tuesday 17 February 2009 22:23:25 Kay Sievers wrote: >> Monolithic versus modular kernels usually >> make about 2+ seconds difference on a recent laptop. > > Thanks for the fact injection. How about a megamodule then? Sounds interesting. The ability to load multiple modules with a single call may help, if such a call could be handled faster than individual calls. Modprobe's modules added by dependencies of the requested module, or modprobe -a could probably use such a facility. Or do you think, the time the kernel needs to be locked can be minimized somehow, so we get more parallelism and less serialization? The current load_module() wraps ~400 lines of pretty heavy code in stop_machine(), if we could possibly make that window smaller, so that multiple instances could prepare some of the work in parallel, and only a fraction of the current work would need to be serialized? If that could be improved for the common distro case of running ~90 modprobe calls on bootup, many of them running in parallel, linking ~100 modules in, all in a time-frame of ~2-3 seconds -- that maybe would attack the real "problem"? Thanks, Kay