<!-- MHonArc v2.4.4 -->
<!--X-Subject: [MUD-Dev] Re: atomic functions -->
<!--X-From-R13: X Q Znjerapr <pynjNhaqre.rate.ftv.pbz> -->
<!--X-Date: Thu, 7 May 1998 15:58:30 -0700 -->
<!--X-Message-Id: 199805072257.PAA02201#under,engr.sgi.com -->
<!--X-Content-Type: text/plain -->
<!--X-Reference: 199805051252.OAA14086#xs1,simplex.nl -->
<!--X-Head-End-->
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<html>
<head>
<title>MUD-Dev message, [MUD-Dev] Re: atomic functions</title>
<!-- meta name="robots" content="noindex,nofollow" -->
<link rev="made" href="mailto:claw#under,engr.sgi.com">
</head>
<body background="/backgrounds/paperback.gif" bgcolor="#ffffff"
text="#000000" link="#0000FF" alink="#FF0000" vlink="#006000">
<font size="+4" color="#804040">
<strong><em>MUD-Dev<br>mailing list archive</em></strong>
</font>
<br>
[ <a href="../">Other Periods</a>
| <a href="../../">Other mailing lists</a>
| <a href="/search.php3">Search</a>
]
<br clear=all><hr>
<!--X-Body-Begin-->
<!--X-User-Header-->
<!--X-User-Header-End-->
<!--X-TopPNI-->
Date:
[ <a href="msg00463.html">Previous</a>
| <a href="msg00465.html">Next</a>
]
Thread:
[ <a href="msg00386.html">Previous</a>
| <a href="msg00433.html">Next</a>
]
Index:
[ <A HREF="author.html#00464">Author</A>
| <A HREF="#00464">Date</A>
| <A HREF="thread.html#00464">Thread</A>
]
<!--X-TopPNI-End-->
<!--X-MsgBody-->
<!--X-Subject-Header-Begin-->
<H1>[MUD-Dev] Re: atomic functions</H1>
<HR>
<!--X-Subject-Header-End-->
<!--X-Head-of-Message-->
<UL>
<LI><em>To</em>: <A HREF="mailto:mud-dev#kanga,nu">mud-dev#kanga,nu</A></LI>
<LI><em>Subject</em>: [MUD-Dev] Re: atomic functions </LI>
<LI><em>From</em>: J C Lawrence <<A HREF="mailto:claw#under,engr.sgi.com">claw#under,engr.sgi.com</A>></LI>
<LI><em>Date</em>: Thu, 07 May 1998 15:57:02 -0700</LI>
<LI><em>Reply-To</em>: <A HREF="mailto:mud-dev#kanga,nu">mud-dev#kanga,nu</A></LI>
<LI><em>Sender</em>: "Petidomo List Agent -- Kanga.Nu version" <<A HREF="mailto:petidomo#kanga,nu">petidomo#kanga,nu</A>></LI>
</UL>
<!--X-Head-of-Message-End-->
<!--X-Head-Body-Sep-Begin-->
<HR>
<!--X-Head-Body-Sep-End-->
<!--X-Body-of-Message-->
<PRE>
On Tue, 5 May 1998 14:52:12 +0200 (MET DST)
Felix A Croes<felix#xs1,simplex.nl> wrote:
> Jon A. Lambert <jlsysinc#ix,netcom.com> wrote:
>> I don't see how any threads are guaranteed execution in C&C, unless
>> they are evntually escalated to single-threading as per your
>> earlier reference. How does atomic prevent another thread from
>> accessing and updating objects, unless you single thread/task it?
> What I wrote is wrong -- if N events are executing and the first one
> to complete succeeds, then the ones that complete after that may all
> fail, so after completion of the first event, none of the events
> executing at that moment will succeed. But in C&C, an event that is
> itself doomed cannot block the progress of another event. Since an
> event can only be doomed by another event that already completed
> successfully, progress is guaranteed in the system as a whole. In
> the worst case scenario above, one event would immediately complete
> successfully.
Rephrasing only:
In the C&C model, the only time an event fails C&C and has to
reschedule is when another event managed to successfully C&C during
its execution. That's the only way you can get a changed object to
cause the C&C failure. Or to put it another way, given N executing or
about to be executing events, at the end of the iteration you are
guaranteed that at least one of them will successfully C&C.
The only reason to degrade the threading model down towards
single-tasking is if you have an event which needs to compleat, but is
failing due to C&C failures caused by other more sprightly events
"getting in there first". The classic scenario on-list is Bubba
digging the Panama Canal.
eg If the "dig panama canal" event were coded to do the whole thing in a
single very long execution, you are it is likely that it would never
C&C due to other shorter/faster events getting in and touching objects
before the "big event" compleats.
C&C has guaranteed thru-put, it just doesn't guarantee much more than
a trickle.
Musing: Do you think when 50 years from now someone does a
restrospective or history of the early years of VR...there'll be an
entry under "Bubba"?
BTW: Jon, how do you handle IO for event failures? Buffer and
release?
--
J C Lawrence Internet: claw#null,net
(Contractor) Internet: coder#ibm,net
---------(*) Internet: claw#under,engr.sgi.com
...Honourary Member of Clan McFud -- Teamer's Avenging Monolith...
--
MUD-Dev: Advancing an unrealised future.
</PRE>
<!--X-Body-of-Message-End-->
<!--X-MsgBody-End-->
<!--X-Follow-Ups-->
<HR>
<!--X-Follow-Ups-End-->
<!--X-References-->
<UL><LI><STRONG>References</STRONG>:
<UL>
<LI><STRONG><A NAME="00386" HREF="msg00386.html">[MUD-Dev] Re: atomic functions</A></STRONG>
<UL><LI><EM>From:</EM> "Felix A. Croes" <felix#xs1,simplex.nl></LI></UL></LI>
</UL></LI></UL>
<!--X-References-End-->
<!--X-BotPNI-->
<UL>
<LI>Prev by Date:
<STRONG><A HREF="msg00463.html">[MUD-Dev] Re: Character maintinence - expenditure of resources</A></STRONG>
</LI>
<LI>Next by Date:
<STRONG><A HREF="msg00465.html">[MUD-Dev] Re: Character maintinence - expenditure of resources</A></STRONG>
</LI>
<LI>Prev by thread:
<STRONG><A HREF="msg00386.html">[MUD-Dev] Re: atomic functions</A></STRONG>
</LI>
<LI>Next by thread:
<STRONG><A HREF="msg00433.html">[MUD-Dev] Re: atomic functions</A></STRONG>
</LI>
<LI>Index(es):
<UL>
<LI><A HREF="index.html#00464"><STRONG>Date</STRONG></A></LI>
<LI><A HREF="thread.html#00464"><STRONG>Thread</STRONG></A></LI>
</UL>
</LI>
</UL>
<!--X-BotPNI-End-->
<!--X-User-Footer-->
<!--X-User-Footer-End-->
<ul><li>Thread context:
<BLOCKQUOTE><UL>
<LI><STRONG>[MUD-Dev] Re: atomic functions</STRONG>, <EM>(continued)</EM>
<ul compact>
<ul compact>
<LI><strong><A NAME="00383" HREF="msg00383.html">[MUD-Dev] Re: atomic functions</A></strong>,
Jon A. Lambert <a href="mailto:jlsysinc#ix,netcom.com">jlsysinc#ix,netcom.com</a>, Mon 04 May 1998, 20:20 GMT
</LI>
<LI><strong><A NAME="00388" HREF="msg00388.html">[MUD-Dev] Re: atomic functions</A></strong>,
Joel Dillon <a href="mailto:emily#cornholio,new.ox.ac.uk">emily#cornholio,new.ox.ac.uk</a>, Tue 05 May 1998, 07:17 GMT
<UL>
<LI><strong><A NAME="00557" HREF="msg00557.html">[MUD-Dev] Re: atomic functions</A></strong>,
Jon A. Lambert <a href="mailto:jlsysinc#ix,netcom.com">jlsysinc#ix,netcom.com</a>, Wed 13 May 1998, 21:32 GMT
</LI>
</UL>
</LI>
</ul>
<LI><strong><A NAME="00386" HREF="msg00386.html">[MUD-Dev] Re: atomic functions</A></strong>,
Felix A. Croes <a href="mailto:felix#xs1,simplex.nl">felix#xs1,simplex.nl</a>, Tue 05 May 1998, 06:25 GMT
<UL>
<LI><strong><A NAME="00464" HREF="msg00464.html">[MUD-Dev] Re: atomic functions</A></strong>,
J C Lawrence <a href="mailto:claw#under,engr.sgi.com">claw#under,engr.sgi.com</a>, Thu 07 May 1998, 22:58 GMT
</LI>
</UL>
</LI>
<LI><strong><A NAME="00433" HREF="msg00433.html">[MUD-Dev] Re: atomic functions</A></strong>,
Felix A. Croes <a href="mailto:felix#xs1,simplex.nl">felix#xs1,simplex.nl</a>, Wed 06 May 1998, 19:37 GMT
<UL>
<LI><strong><A NAME="00459" HREF="msg00459.html">[MUD-Dev] Re: atomic functions</A></strong>,
Shawn Halpenny <a href="mailto:malachai#iname,com">malachai#iname,com</a>, Thu 07 May 1998, 14:12 GMT
<UL>
<LI><strong><A NAME="00558" HREF="msg00558.html">[MUD-Dev] Re: atomic functions</A></strong>,
Jon A. Lambert <a href="mailto:jlsysinc#ix,netcom.com">jlsysinc#ix,netcom.com</a>, Wed 13 May 1998, 21:41 GMT
<UL>
<LI><strong><A NAME="00584" HREF="msg00584.html">[MUD-Dev] Re: atomic functions</A></strong>,
Shawn Halpenny <a href="mailto:malachai#iname,com">malachai#iname,com</a>, Thu 14 May 1998, 20:00 GMT
</LI>
</UL>
</LI>
</UL>
</LI>
</UL>
</LI>
</ul>
</LI>
</UL></BLOCKQUOTE>
</ul>
<hr>
<center>
[ <a href="../">Other Periods</a>
| <a href="../../">Other mailing lists</a>
| <a href="/search.php3">Search</a>
]
</center>
<hr>
</body>
</html>
