From owner-freebsd-hackers@FreeBSD.ORG Sat Dec 31 21:52:33 2011 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 010BD106564A for ; Sat, 31 Dec 2011 21:52:33 +0000 (UTC) (envelope-from julian@freebsd.org) Received: from vps1.elischer.org (vps1.elischer.org [204.109.63.16]) by mx1.freebsd.org (Postfix) with ESMTP id CA5898FC08 for ; Sat, 31 Dec 2011 21:52:32 +0000 (UTC) Received: from julian-mac.elischer.org (c-67-180-24-15.hsd1.ca.comcast.net [67.180.24.15]) (authenticated bits=0) by vps1.elischer.org (8.14.4/8.14.4) with ESMTP id pBVLqTuF073591 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO); Sat, 31 Dec 2011 13:52:31 -0800 (PST) (envelope-from julian@freebsd.org) Message-ID: <4EFF8449.1060800@freebsd.org> Date: Sat, 31 Dec 2011 13:53:13 -0800 From: Julian Elischer User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.4; en-US; rv:1.9.2.25) Gecko/20111213 Thunderbird/3.1.17 MIME-Version: 1.0 To: arrowdodger <6yearold@gmail.com> References: <4EFE5806.3090000@freebsd.org> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-hackers Subject: Re: Using symbolic execution for analyzing scheduler performance? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 31 Dec 2011 21:52:33 -0000 On 12/30/11 11:34 PM, arrowdodger wrote: > On Sat, Dec 31, 2011 at 4:32 AM, Julian Elischer > wrote: > > On 12/30/11 9:52 AM, arrowdodger wrote: > > - OS kernel calls scheduler functions in some defined order. > > > The OS doesn't really call the scheduler in that way. > all sorts of threads of execution jump into the scheduler from > all sorts of places and > the internal state of the scheduler changes with these calls. > Sometimes those calls > never return, and sometimes they return a long time later.. As > I said, it's a very > complicated interface. > > > Oh, threads. Yes, this imposes unimaginable complexity on what i'm > proposing. > > > What do you think? Does it make any sence, or i should just > return under my > rock? > > > no, come out from your rock.. If you are interested in the > scheduler, by all means > go and read it and try and understand it, and then come back to > us if you do have ideas. > > > Yeah, i think it's what i should've done in first place, before > dumping by brain to ML. > Okay, i will try to get an idea of how schedulers work in detail and > after that will try to find parts of it, which can be automatically > verified. > > BTW, is there any documentation on how write schedulers for FreeBSD, > or at least, ULE specification? there is a paper that was presented somewhere on ULE, but the best source of information is of course the code.. start by reading the 4bsd scheduler.. as it's simpler.. > > I don't think your idea is really bad but I think you > underestimate the difficulty of the task. > > PS: Sorry for my english, i hope you understood what i've > been trying to > say. > > your english is fine.. what do you normally speak? > > > Russian. there are a lot of russian developers so you should be able to find someone if you need explanations in Russian.. > > (and you are not really 6 years old, are you? :-) > > > Yeah, i've grown up a little, since then. > > Thanks for your insight!