Simon Bennett (simonb++at++wormald.com.au)
Thu, 14 Sep 1995 12:21:15 +1000 (EST)
> > happier solution. You can use arena's either directly through IRIX (see the
> > manpages for usinit et al) or through Performer - pfDataPools etc...
> Well, I'm not sure why you say that IPC calls don't co-exist happily with
> IRIX REACT semaphores and shared memory. This just doesn't follow what
> system I have running.
Two reasons:
1) The IRIX System Programming Guide says they don't
2) We we're orginally using SysV IPC, and although it worked, it was
slow and a "bit dodgy" (for want of a better expression) when we
moved to IRIX arena IPC, speed and reliability went up.
I'm not saying you can't use SysV IPC, (you can, we did, and you obviously
do), it's just that there seems to be some pitfalls ( and they don't seem to
be MP-safe either - I'd be very interested to hear your experiences with
this). To be completely fair, when we were using SysV IPC, we were on IRIX
5.0 - which wasn't entirely stable in itself, so maybe the
"incohabitability" problems have been solved?
> For my underlying drivers that I have ported to
> about 4 different UNIX platforms, I use System V IPC semaphores and
> shared memory segments and have had absolutely no problems using it under
> a performer 1.2 application. The speed hit may be true, but since the
> SYS V semaphores are portable its just a matter of what you are after on
> your product and what your programmers are familiar with. I have to,
> however, agree that the IRIX REACT seamphores and shared memory segments
> are faster, and a preferred choice on SGI platforms -- its just I hate to
> write code that is completely unusable on other platforms unless I have a
> resource bottleneck by that choice.
Fair enough. I agree with you 100%. For our applications, speed is the
main thrust. Portability is irrelevant - we're not going to be running
Performer on anything else besides SGI's in the near future. Just for
interests sake, what version of IRIX have you been running on? What
platforms? Maybe that's where the problem lies?
I still think thou, that if portability is not an issue, then IRIX arenas
are the way to go. It's faster and (I think) simpler (for programmers not
familiar with either - I think arenas are easier to grasp - peronal opinion
only - I'd been using sockets and SysV IPC for years before I moved to
VisSim and found the arena IPC refreshingly simple and efficient). (This
isn't an invitation to start a flame war on winopen() vs X BTW) :)
+----------------------------------------------------------------------------+
Simon Bennett simonb++at++wormald.com.au
Wormald Technology Advanced Systems Engineering Ph: +61 2 9981 0611 (x512)
Meeting - an event where you take minutes and waste hours.
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