[IGSTK-Developers] problem with threads???

[David Gobbi]

Hi Kevin,

It is definitely true that multi-threading in C++ has one very important 
safety drawback: threads share memory with one another and it is very 
hard to validate that one of the threads isn't touching memory that it 
isn't supposed to.  Hence the idea of using multiple processes instead 
of multiple threads has come up in our technical discussions.  The only 
real advantage of threads is efficiency, since all memory is shared 
instead of data being passed over sockets or pipes.

Overall, though, I don't see why threads are any less deterministic than 
other models for concurrent programming (haven't read the paper yet).  I 
just see them as harder to validate and harder to debug, particularly in 
a language like C++ that wasn't designed with multi-threading in mind.

 - David


Kevin Cleary wrote:
>
> As noted by Ziv Yaniv from our group - see the May issue of IEEE 
> Computer (obviously not as good as the previous issue with our article ;)
>
>  
>
> It really advocates not using threads as they cause programs to be 
> nondeterministic, and very unsafe in many cases. This goes against the 
> IGSTK spirit of extreme safety.
>
>  
>
> I don't think we should change anything we did for the proposal - this 
> is just FYI
>
>  
>
> Kevin
>
>  
>
> The Problem with Threads
> Edward A. Lee 
> <http://search2.computer.org/advanced/Author_Result.jsp?qtype=3&select=50&qOpt1=DC_CREATOR&sortOrder=d&queryName=Edward%20A.%20Lee>, 
> University of California, Berkeley
>
> Full Article Text: Download PDF of full textBuy this article 
> <https://newton.computer.org/DocDelivery/Shopping.nsf/AddToCart?OpenAgent&U=http://csdl.computer.org/dl/mags/co/2006/05/r5033.pdf&T=The%20Problem%20with%20Threads>
>
> **DOI Bookmark: **http://doi.ieeecomputersociety.org/10.1109/MC.2006.180
>
> *Abstract*
>
> For concurrent programming to become mainstream, we must discard 
> threads as a programming model. Nondeterminism should be judiciously 
> and carefully introduced where needed, and it should be explicit in 
> programs.
>
>  
>
> *Back to Top 
> <http://csdl2.computer.org/persagen/DLAbsToc.jsp?resourcePath=/dl/mags/co/&toc=comp/mags/co/2006/05/r5toc.xml&DOI=10.1109/MC.2006.180#top> 
> *
>
> *Additional Information *
>
> *Index Terms-* Programming paradigms, Threads, Nondeterminism, Design 
> patterns, Coordination languages
>
> **Citation:**  Edward A. Lee, "The Problem with Threads," /Computer/, 
> vol. 39,  no. 5,  pp. 33-42,  May,  2006.
>
>  
>
>  
>
>  
>
> ------------------------------------------------------------------
>
> Kevin Cleary, Ph.D.                        Work phone: 202-687-8253
>
> Associate Professor                        Work fax: 202-784-3479
>
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>
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>
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>
> -------------------------------------------------------------------
>
>  
>
> -----Original Message-----
> From: Ziv Yaniv [mailto:zivy at isis.imac.georgetown.edu]
> Sent: Saturday, May 06, 2006 11:45 PM
> To: cleary at isis.georgetown.edu
> Subject: misc
>
>  
>
> Hi Kevin,
>
>  
>
> I forgot to let you know I'd be working from home on monday.
>
>  
>
> The more interesting thing is a paper in the last issue of computer 
> (got it today). From what I've seen of the upcoming IGSTK proposal 
> part of it includes multi-threading. In this issue of computer there 
> is a paper called "The Problem with Threads". It really advocates not 
> using threads as they cause programs to be nondeterministic, and very 
> unsafe in many cases. This goes against the IGSTK spirit of extreme 
> safety.
>
>  
>
>                            Ziv
>
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