Date: Sat, 31 Dec 2011 13:53:13 -0800 From: Julian Elischer <julian@freebsd.org> To: arrowdodger <6yearold@gmail.com> Cc: freebsd-hackers <freebsd-hackers@freebsd.org> Subject: Re: Using symbolic execution for analyzing scheduler performance? Message-ID: <4EFF8449.1060800@freebsd.org> In-Reply-To: <CALH631n-V8kMFm=STRwM__53otGXaVqa9nwoAM-VA4-Qfx=RzA@mail.gmail.com> References: <CALH631=v690XayAix=vX7NTyj%2BSnML%2BMpzFC6i0Ms0Bg%2BEaKTw@mail.gmail.com> <4EFE5806.3090000@freebsd.org> <CALH631n-V8kMFm=STRwM__53otGXaVqa9nwoAM-VA4-Qfx=RzA@mail.gmail.com>
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On 12/30/11 11:34 PM, arrowdodger wrote: > On Sat, Dec 31, 2011 at 4:32 AM, Julian Elischer <julian@freebsd.org > <mailto:julian@freebsd.org>> 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!
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