Re: Concurrency in Gnat 3.05?

[jsa@alexandria (Jon S Anthony)]

In article <dewar.837815167@schonberg> dewar@cs.nyu.edu (Robert Dewar) writes:

> Jon said
> 
> "The point is that time slicing behavior is system dependent.  For
> example, GNAT on Solaris maps tasks to threads and they will behave as
> you were expecting (switching context for IO, etc.)"
> 
> Yes, in fact the default behavior on Solaris clearly violates the Ada 95
> standard in that time slicing does occur. We are investigating the use
> of the real time priority levels in Solaris which should make it possible
> to correct this incorrect behavior.

While the language only defines the defaul FIFO policy, could you use
the bit in D.2.2(6) which says that in the absence of a
Task_Dispatching_Policy pragma, the dispatching policy is unspecified
to "justify" this behavior?  Or is this an unrelated thing?


"(6)
       A task dispatching policy specifies the details of task
dispatching that are not covered by the basic task dispatching
model. These rules govern when tasks are inserted into and deleted
from the ready queues, and whether a task is inserted at the head or
the tail of the queue for its active priority. The task dispatching
policy is specified by a Task_Dispatching_Policy configuration
pragma. IF NO SUCH PRAGMA APPEARS IN ANY OF THE PROGRAM UNITS
COMPRISING A PARTITION, THE TASK DISPATCHING POLICY FOR THAT PARTITION
IS UNSPECIFIED." (emphasis mine.../jsa)

/Jon
-- 
Jon Anthony
Organon Motives, Inc.
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Belmont, MA 02178

617.484.3383
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