Re: Peterson's Algorithm in java, sequencial instruction execution ?

From:
"Daniel Pitts" <googlegroupie@coloraura.com>
Newsgroups:
comp.lang.java.programmer
Date:
2 Dec 2006 11:03:27 -0800
Message-ID:
<1165086207.165998.283550@l12g2000cwl.googlegroups.com>
xmarlawx@gmail.com wrote:

Mike Schilling wrote:

If you want to guarantee that thread A sees a change to memory made by
thread B, you need to use synchronization.


I'm sorry Mike, but if you refer to standard Java synchronization
facility I believe you are wrong.
This is exactly what Peterson's algorithm is suppose to do,
synchronization, without the use
of language construct such as "synchronized" or particular hardware
instructions such as "Test & Set", the so called atomic actions.

Also, my point is not related to threads, but only to simple sequence
of instructions in a
program (in this case written in Java for a recent JVM 5.*).
I know that the instructions of different running threads can be (and
will be) interleaved but I've got to read on wikipedia that also some
instructions, in normal programs can be interleaved for efficency
purpose and that's what would make the whole algorithm to not work
anymore thus having the two threads not synchronized anymore.

The link I've wrote in the first message would explain more.

Thanks again.


Have you head this?

<http://java.sun.com/docs/books/jls/second_edition/html/memory.doc.html#28330>

This describes how Volitile affects memory access. I don't know if it
is enough, but it might be useful.

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