[cpp-threads] "Agenda" for august 23-25 concurrency meeting (CORRECTION)

[Hans Boehm]

Herb points out that my weekdays are of course off.  The atomics
discussion is on Wednesday, memory model discussion on Wednesday and
Thursday, and threads API discussion on Thursday and Friday.

We'll start at 9:00a.m. on Wednesday and finish around 4:00p.m. on Friday.
Sorry about the confusion.

Hans

On Mon, 14 Aug 2006, Boehm, Hans wrote:

> Here is a quick attempt at a list of technical topics that I would hope
> to cover at the meeting.  I would prefer to keep this very informal, and
> attach only rough times to these, since I expect the list to change
> before and during the meeting.
>
> Very roughly, I would like to aim for:
>
> Monday Morning: Atomics discussion.  (Herb - is 9:00 a good starting
> time?)
>
> Monday immediately after lunch: Brief overview of OpenMP status, if
> there is a volunteer.
>
> Rest of Monday afternoon, Tuesday morning: Memory model discussion,
> starting with more detailed presentation.  Herb - Would you also like to
> present? (We may want to start this Monday late morning, since some of
> the atomics issues are not really separable from the memory model.)
>
> Starting sometime Tuesday afternoon: Threads API discussion.
>
> Wednesday afternoon, time permitting: library discussion.
>
> My expectation is that we will close at around 4:00 on Wednesday, and
> will probably start to lose people shortly before that.
>
> Please let me or the list know if I omitted something you think is
> important.
>
> Technical issues:
>
> Atomics
> 	Two levels of atomics (C-style + templates)?
> 	Bottom level operates on plain scalars, volatiles, or special
> data?
> 		Does backward compatibility matter?
> 	double-word CAS?
> 	Does default atomic assignment include trailing fence?
> 		I.e. does it behave like Java volatiles?
> 		(Raised again by Herb's paper.)
> 	Other details?
>
> Memory model
> 	Fairly detailed presentation (Hans and/or Clark)
> 	Construction of statics thread-safe by default?
> 		A tentative decision would be nice.
> 	Treatment of infinite loops.
> 	Do ordered atomics effectively order "raw" (unordered)
> 		atomic operations?
> 		(See
> http://www.decadentplace.org.uk/pipermail/cpp-threads/2006-August/000989
> .html)
> 	Other issues?
>
> Threads API
> 	Approach?
> 		I (Hans) think the alternatives are
> 			A) Boost + modifications
> 			B) More drastic redesign
> 			C) fallback: something minimal to let us talk
> 			about threads in the standard while using
> 			Boost/pthreads/win32/... in real programs
> 	Issues that are probably open either way:
> 		Constructor/destructor handling.
> 		Exception propagation past joins?
> 		Any cancellation support?
> 	Probably many other issues.
>
> Library Issues
> 	Can we start a list?
> 	Can we leave basic_string as is?
> 	Do I/O operations introduce synchronizes-with relationships?
> 	Which I/O operations are atomic?
> 	Who is willing to look at these issues?
> 	Probably many other issues.
>
> Recommended prereading (Hans' biased priority ordering):
> 	Draft of the Nelson & Boehm memory model/sequencing paper which
> we hope
> 	to get out by Friday or so.  If you can't wait until then, the
> current
> 	strawman memory model proposal.
> 	Herb's Prism paper.
> (http://www.decadentplace.org.uk/pipermail/cpp-threads/2006-August/00100
> 9.html)
> 	N2047 atomics proposal.
> 	Pete Becker's thread library proposal (N1907).  (There are
> competing proposals
>       from at least Lawrence and Kevlin as well, but they are less
> concrete, and
> 	probably less important to scrutinize in detail at this stage.)
> 	Except for Herb's paper, these are/will be all referenced from
> 	http://www.hpl.hp.com/personal/Hans_Boehm/c++mm/.
> 	Lawrence's summary of the other threads API discussion at the
> Berlin
> 	C++ meeting (Ugly version at
>
> http://www.decadentplace.org.uk/pipermail/cpp-threads/2006-April/000928.
> html.
> 	Extract to html file.)
> 	Anything else that's referenced from the c++mm page and you find
> 	interesting.
>
>
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