From owner-freebsd-hackers@FreeBSD.ORG Fri Mar 25 12:51:38 2005 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from green.homeunix.org (freefall.freebsd.org [216.136.204.21]) by hub.freebsd.org (Postfix) with ESMTP id 81A9616A4CE; Fri, 25 Mar 2005 12:51:38 +0000 (GMT) Received: from green.homeunix.org (green@localhost [127.0.0.1]) by green.homeunix.org (8.13.3/8.13.1) with ESMTP id j2PCpbgC019509; Fri, 25 Mar 2005 07:51:37 -0500 (EST) (envelope-from green@green.homeunix.org) Received: (from green@localhost) by green.homeunix.org (8.13.3/8.13.1/Submit) id j2PCpadc019508; Fri, 25 Mar 2005 07:51:36 -0500 (EST) (envelope-from green) Date: Fri, 25 Mar 2005 07:51:36 -0500 From: Brian Fundakowski Feldman To: Andriy Tkachuk Message-ID: <20050325125136.GA13857@green.homeunix.org> References: <006401c53128$e6c6d390$090210ac@BORJA> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <006401c53128$e6c6d390$090210ac@BORJA> User-Agent: Mutt/1.5.6i cc: freebsd-hackers@freebsd.org Subject: Re: contributing to fbsd X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 25 Mar 2005 12:51:38 -0000 On Fri, Mar 25, 2005 at 04:23:33PM +0530, Andriy Tkachuk wrote: > Hi folks. > > I'd like to contribute to kernel code. > > I have some experience: 8 years of using fbsd > (it's actually my favourite os) and last couple years > i've studing kernel deaply using many good books like > - Bach's Design of UNIX > - Kusick's 44BSD > - Vahalia's UNIX Internals > - Stalling's Operating System > and even > - Tanenbaum's Modern Operating Systems > which i didn't liked vety much :) > > my main interest is in such part of OS as > scheduling, smp, threading and resource allocation. > > But i didn't code anything in this field yet > (exept patching [2005/01/26] threads/76690threads fork hang in child > for (-lc_r & -lthr) > in wich anyone doesn't interesting as it appeared )) PRs can get lost or misfiled... it's just human nature. > It is obviously, that one can't read theory all the time > without practice because the staff becames uninteresting )) > > Last time Linux kernel appeared to be more successfull > in threading, smp, resource allocation and stuff with is > needed under heavy loaded multiprocess systems and > i'd like my favourite os to be successful in this field as well ) > I understand, that this is not the question of couple man/months > and that fbsd slowly but confidently succeed in this direction. > > Last time i was very interested in resource allocation stuff. > Bonwick's VMEM O(1) universal allocator appeared to be > very interesting: > http://www.usenix.org/event/usenix01/bonwick.html > as good as his cpu-wise magazines addition to > slab allocator which scales allocation on adding cpus. > Solaris use this approach. > > My question is: does folks interested in implementation > of this stuff in fbsd kernel? There is already an implementation of a slab-based allocator (uma(9)), but this is only for the kernel. There is currently more of a growing need for a faster MP/threading-oriented userland allocator. > As I see now there is for example O(n) algorithm for > process IDs allocation... In linux it is addressed > using bit-mapping (as far as i understand). > In Oct 2003 there was topic in this list: > "Some mmap observations compared to Linux 2.6/OpenBSD" > in which allocation in mmap was discussed. > As it was appeared that fbsd use O(n) algorithm here compared > to Linux and OpenBSD. I don't know the presend state of this. Recently added was a generic subsystem for generating and managing unique binary identifiers, for example, pids. The VM map algorithms are the same as ever, though. They use linear traversal along with a cached reference to the last lookup. There are certainly some workloads that should benefit from this, so it definitely could be something you could work on. -- Brian Fundakowski Feldman \'[ FreeBSD ]''''''''''\ <> green@FreeBSD.org \ The Power to Serve! \ Opinions expressed are my own. \,,,,,,,,,,,,,,,,,,,,,,\