🚀 go-pugleaf

In article <123909@sun.Eng.Sun.COM> rajivp@sun.UUCP (Rajiv Patel) writes:
>  state information. For VLIW machines it seems that instruction continuation
		      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>  might be better for restart might first need to roll back partially completed
   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>  operations. 
   ^^^^^^^^^^^
>

This depends on how often you expect roll back to be necessary.  From the
perspective of a single instruction, all the data I have ever seen indicates
that exceptions occur very infrequently.  (on most machines, the most
frequent exception is a page fault).  So, is this really an issue?
In addition, what fraction of time does the lost work account for in
comparison to the amount of time spent by the OS just trying to figure
out what the exception was and how to deal with it?

Mike Shebanow

PS: I do not consider OS calls (traps) or interrupts to be an exception --
the hardware can plan for those and hence not require any roll back.
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Disclaimer: the opinions expressed here are my own, not Motorola's.