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Date:      Fri, 28 Jul 2006 14:22:37 +0200
From:      Alexander Leidinger <Alexander@Leidinger.net>
To:        Robert Watson <rwatson@freebsd.org>
Cc:        hackers@freebsd.org, Joel Dahl <joel@freebsd.org>
Subject:   Re: cvs commit: www/en/projects/ideas index.sgml
Message-ID:  <20060728142237.lhocfctqugoocc48@netchild.homeip.net>
In-Reply-To: <20060728092503.U4612@fledge.watson.org>
References:  <200607280705.k6S7585g094248@repoman.freebsd.org> <20060728092503.U4612@fledge.watson.org>

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Quoting Robert Watson <rwatson@freebsd.org> (from Fri, 28 Jul 2006 =20
09:52:33 +0100 (BST)):

[moving to hackers@... feel free to redirect if you think there's a =20
more appropriate list]

>
> On Fri, 28 Jul 2006, Joel Dahl wrote:
>
>> Modified files:
>>   en/projects/ideas    index.sgml
>> Log:
>> -  Extend the ktrace project with a new task. [1]

[adding some warnings to this project]

Thanks for reviewing and the heads up regarding problems which may =20
arise. Yes, we should add them to the entry.

> BTW, a problem that has occurred a number of times in the past is that
> people have approached us with implementations of ideas in the idea
> list that it has later transpired we aren't actually interested in
> (sometimes at all).  I think it might not be a bad idea to sprinkle the

My impression is, that we lack some committers which not only have =20
time to review the submissions, but also have the necessary domain =20
specific knowledge at the same time.

> idea list with some additional cautionary language -- often ideas
> listed there are things to explore, not to adopt without very careful
> consideration.  For example, the "FPU subsystem overhaul", "Process

Uhm... the FPU one... ok. AFAIK bde reviewed it. I haven't seen the =20
review (or I don't remember it), but so far it looks like it would be =20
beneficial to commit it (AFAIR). I'm not able to review the code (I =20
lack the necessary domain specific knowledge), but I wanted to give it =20
a try on my system and then send a mail to arch to get some technical =20
reasons why to not commit commit it.

Similar for the new TCP checksumming code. Initially there was a =20
problem, it got fixed, and now nobody takes care of it since everyone =20
seems to think "it's flawed". At least this is the impression I got.

> checkpointing", "Pluggable disk shceduler", "Magic Symlinks", "NFS
> Lockd (kernel implementation)", and several others -- the task here
> often isn't to port/write the code, the task is to port/write and then
> perform a detailed and careful evaluation of the changes to decide
> whether they are a good idea, and then consider adopting the code only
> if the evaluation suggests it is a good idea and after significant
> refinment.

So far we got not much responses from committers/developers. There's a =20
lot of interest in working on some of the entries, but so far we don't =20
get much review for the entries/ideas themself. Any refinement is =20
welcome and appreciated. So if someone has some thoughts about =20
specific entries: please, share them with us.

> Some of the ideas on this list are distinctly "explore this direction
> as a computer scientist, not a code hacker" sorts of problems -- for
> example, the "Process checkpointing" task seems to suggest that if you
> can read the DFBSD repository and write some C code, you're set.  In
> fact, this is not remotely the case.  Checkpointing is a very difficult
> problem in computer science, with little consensus on how it should be
> done (and indeed whether it should be done at all) by general purpose
> operating systems.  Not only that, but we would not adopt the DFBSD
> implementation as-is, as it solves a few of the easy problems, and none
> of the hard ones (i.e., security).  The requirements here aren't just
> the ability to write code, but an understanding of distributed systems,
> our application/execution model, a strong understanding of the
> performance and security requirements, and willingness to not just look
> at code but the extensive research literature on this topic.

AFAIR the process checkpointing in DFly has to be enabled (or am I =20
mixing this up with the magic symlinks?) in the kernel. And the man =20
page contains some text what is possible and what not, and about =20
security implications. Yes, they don't use a model which is able to =20
solve all cases, but for some cases where the programs (those which =20
don't make heavy use of I/O and thus can open/close I/O channels when =20
they are needed) are written to make use of this feature, you can make =20
some users happy and the developers can concentrate at the problem at =20
hand. So it's one of those 80/20 solutions. While I agree that a 100% =20
solution would be nice, I think an implementation of this in -current =20
would be nice to have.

> I think people often grab ideas from the list thinking that if
> implemented as described, they will get committed, and this is not the
> case.  In many of the sorts of "scientific" cases it's likely we'll
> look at the results and say, "Oh, that was a bad idea", or maybe
> slightly more likely, "Oh, hmm, not so sure about that".  The existing

Joel and I already talked briefly about an "we don't do that" or "been =20
there, done that, wasn't a good idea" page because of this.

> cautionary language captures that there might be disagreements on the
> specifics, but fails to capture that there may be disagreements on the
> fundamental ideas themselves.  I like the ideas list idea a lot, and

Ok, we should change that. Thanks for providing a big picture view for =20
those of us which don't see the forest while sitting in front it...

> don't want to see it removed, but I also don't want people getting the
> false impression that this is a "todo" list.  Some items are todo items
> and obvious short-order commit candidates, others are out-there ideas
> that have potential and should be characterized as "high risk" when it
> comes to the results actually being used.  Maybe what we should be
> thinking about is classifying the todo list items into rote items
> (things where the chances of adoption of a decent implementation are
> high, subject to review) and researchy things (where the chances of
> adoption are low, not just because the chances of a good implementation
> are low, but because there are lots of open and very difficult
> questions involved).  This would help prevent misunderstandings, if
> nothing else.

We need some reviewers here... while I'm able to come up with a nice =20
technical description of roughly expressed ideas (as long as I get the =20
idea), I'm not a TRB and as such aren't aware of every implication. =20
And some ideas are expressed in a way which make them sound like it's =20
"common knowledge to people which work in this field" (ATM I refer to =20
the NFS lockd in kernel implementation idea).

So: helping hands are welcome!

Thanks for taking some time to review some parts of the list.

Bye,
Alexander.

--=20
All great discoveries are made by mistake.
=09=09-- Young

http://www.Leidinger.net    Alexander @ Leidinger.net: PGP ID =3D B0063FE7
http://www.FreeBSD.org       netchild @ FreeBSD.org  : PGP ID =3D 72077137




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