[PRL] Fwd: "Threads Considered Harmful" in the news

[Mitchell Wand]

---------- Forwarded message ----------
From: Gene Cooperman <gene at ccs.neu.edu>
Date: Jan 23, 2007 12:49 PM
Subject: Re: [PRL] "Threads Considered Harmful" in the news
To: Matthias Felleisen <matthias at ccs.neu.edu>
Cc: Mitchell Wand <wand at ccs.neu.edu>, PRL <prl at lists.ccs.neu.edu>, Gene
Cooperman <gene at ccs.neu.edu>

If it helps, I can throw in two data points coming from the systems side.
1.  In C/C++, OpenMP is intended to provide a higher level abstraction
        for shared memory that is less dangerous.  Also, MapReduce
        was invented primarily for distributed memory --- not for
        shared memory.  Using it on multi-core chips is okay, but there
        are dangers of excessive pressure on the cache from competing
        processes, and of limited bandwidth from teh multi-core chip
        to RAM.
2.  Haskell is indeed of interest in things like Grid computations ---
        especially in Europe.  It's still at a somewhat experimental
        stage, but at one recent workshop, I met someone who recently
        completed a PhD (now at Heriot-Watt), who used Haskell on the
        Grid for a major computation.  He reports that while the sequential
        application in Haskell was much slower than C/C++, the
        parallelized Grid application came much closer in speed.
        But even more interesting, the Haskell code was
        _eight times_ smaller in size than the C/C++ code.
        That would be a big win.  (I have his slides if you're interested.)
                                                        - Gene

On Tue, Jan 23, 2007 at 09:43:15AM -0500, Matthias Felleisen wrote:
> I am extremely pleased to see that I am wrong in that regard. --
> Matthias
>
>
> On Jan 23, 2007, at 9:39 AM, Mitchell Wand wrote:
>
> >Not entirely true (see, eg, http://www.oreilly.com/catalog/gnuext/).
> >
> >But I was talking about being active in the scientific space, not
> >the publishing space.
> >
> >--Mitch
> >
> >On 1/23/07, Matthias Felleisen <matthias at ccs.neu.edu> wrote: I am
> >pretty sure that OReilly has an explicit policy against
> >publishing anything concerning parenthetical languages. -- Matthias
> >
> >
> >On Jan 23, 2007, at 7:45 AM, Mitchell Wand wrote:
> >
> >> This meme has now reached O'Reilly Radar, along with Erlang,
> >> Haskell, and E.  Scheme needs to play in this space!!
> >>
> >> --Mitch
> >>
> >> http://radar.oreilly.com/archives/2007/01/threads_conside.html
> >> Threads Considered Harmful
> >> By Nat Torkington on January 23, 2007
> >> Professor Edward A. Lee from the EECS department of UC Berkeley
> >> wrote The Problem With Threads (PDF) last year. In it, he observes
> >> that threads remove determinism and open the door to subtle yet
> >> deadly bugs, and that while the problems were to some extent
> >> manageable on single core systems, threads on multicore systems
> >> will magnify the problems out of control. He suggests the only
> >> solution is to stop bolting parallelism onto languages and
> >> components--instead design new deterministically-composable
> >> components and languages.
> >>
> >> This paper reflects two trends we see here at Radar: the first is
> >> towards multicore systems and the growing importance of distributed
> >> execution; the second is the increasing relevance of languages like
> >> Erlang, Haskell , and E. The growth of multicore is significant: if
> >> you want your program to run faster, the days of buying faster
> >> hardware are coming to an end. Instead, we're looking at a time
> >> when you must make your program run faster on more (slow) hardware.
> >> Enter parallel programming, clusters, and their hyped big brother
> >> "grid computing".
> >>
> >> Google have obviously faced this problem and solved it with
> >> MapReduce. Lee argues that this kind of coordination system is how
> >> we solve the problem of threads' nondeterminism. It nicely
> >> parallels (heh) the way that database sharding has become the way
> >> to solve scalability (see the Flickr war story for example). For
> >> this reason we're watching Hadoop, the open source MapReduce
> >> implementation, with interest. (There are also MapReduce
> >> implementations in Perl, Ruby, and other languages)
> >>
> >> MapReduce is built on a technique from the Lisp programming
> >> language. As the need for speed forces us out of our single core
> >> procedural comfort zone, we're looking more and more at "niche"
> >> programming languages for inspiration. Haskell has quite the
> >> following among the alpha geeks we know (e.g., the Pugs project),
> >> and OCaml has a small but growing group of devotees. Then there was
> >> the huge interest in Smalltalk at Avi Bryant's OSCON talk last year
> >> ( SitePoint blogged about it here).
> >>
> >> Tags: erlang google hadoop haskell languages mapreduce ocaml
> >> parallel programming smalltalk threads
> >> _______________________________________________
> >> PRL mailing list
> >> PRL at lists.ccs.neu.edu
> >> https://lists.ccs.neu.edu/bin/listinfo/prl
> >
> >
> >
>
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