[fpc-devel] Linux thread priority mess (and possible implementation)

[Hans-Peter Diettrich]

Paul van Helden schrieb:

> "Threads are evil"? 
> http://www.eecs.berkeley.edu/Pubs/TechRpts/2006/EECS-2006-1.pdf
> 
> Interesting view point. Perhaps that is why FPC doesn't bother too much 
> about thread priorities? :-)

IMO the author neglects the existence of realtime systems, which have to 
deal with concurrent processes and shared resources, as well as the 
existence of multi-user multi-tasking systems. Such systems exist since 
many decades, and the synchronization techniques have been researched 
sufficiently - I learned all that in the early 70s.

Of course such "cooperative" systems do not work without proper 
synchronziation, but IMO not threads are bad per se, instead the 
assumptions of the author simply are impractical. With such assumptions 
the use of shared files, filesystems or other resources are bad as well 
- but what should that mean to software writers? Should we return to 
"safe" single-tasking batch systems, or should we continue to share 
resources with the *appropriate* synchronization mechanisms, at the 
responsibility of the coder?

We all know that writing software is bad, from a 
mathematical/philosophical VP, because nobody could proof the 
correctness of a program till now, and that because almost nobody can 
(or is willing to) provide the required information about the goal of a 
non-trivial program. So I think that we can continue to do our very best 
in writing useful code, even if it can not be verified by purists :-]

DoDi