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September 2004

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[threads-standard-discuss] MP standardization proposal
by Daniel Barlow 07 Dec '04

07 Dec '04

Welcome to the threads-standard-discuss mailing list. It was created as a result of discussion at the Libre Software Meeting in Bordeaux in July 2004, as a venue for creating a portable de facto standard for use by multithreaded Common Lisp code. I have prepared an initial draft specification entitled BORDEAUX-MP, based on CLIM-SYS (and the needs of McCLIM, which are in fact not quite the same), which is available at http://cvs.telent.net/cgi-bin/viewcvs.cgi/bordeaux-mp/Specification?view=ma… Eventually there will also be a sample implementation to go with it, using code borrowed from McCLIM. I invite comments/feedback/flames from all interested parties. Points which have been raised so far include 1) behaviour of specials in a new thread: "did you just make it undefined so that the SBCL implementation would be simpler?" I propose to add a list of specials which automatically get thread-local bindings in each new process: something like ACL's *cl-default-special-bindings* <URL:http://www.franz.com/support/documentation/6.1/doc/pages/variables/excl…> 2) "condition variable" is an unfortunate name as there is already a similarly named but entirely different CONDITION object in CL I don't have any good ideas about this one. 3) A process-state reader might be nice I personally don't see the point, much, unless the semantics of its allowable values are also defined. (Personal position: I'm far more concerned about the ability to write real threaded applications than I am about writing a replacement for top(1) in CL) 4) Some form of control over process priority This might be useful if you have for example a foreground display process that you wish to remain responsive, and a background computation task that only needs to run when nothing else is happening. On the other hand, it might be a fast track to priority inversion and some form of starvation. Discuss. A handy summary of some of the various terms involved is at <URL:http://www.cs.columbia.edu/~hgs/os/sync.html>, for anyone wanting definitions -dan -- "please make sure that the person is your friend before you confirm"

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