Re: How to use power of Dual/ Quad core Processors in Applet?

Lew <lew@lewscanon.nospam>
Mon, 23 Jul 2007 09:02:32 -0400
Lew wrote:

pkriens wrote:

The Java memory model allows the caches of the processors to differ
for variables that are not synchronized or volatile. So on processor A

Not accurate. It also allows them to differ for variables that are
volatile or accessed in a synchronized way, at times. It also requires
that non-volatile variables and those accessed outside synchronized
blocks follow certain visibility rules.

you can read a different value for variable x than on processor B
until they are synchronized. Code that works well on a single
processor because there is only one memory can fail subtly on multiple
processors. Obviously the code is wrong, but I think it makes sense to
schedule Java programs on a single CPU unless specifically allowed.

So you are suggesting that one not fix broken code, instead just try to
get your customers not to run it on multi-processor machines? I cannot
imagine any responsible developer advocating such a practice.

And it isn't "code hat works well o0n a single processor"; it's code
that is equally broken on a single processor. What an irresponsible

You are aware that single-processor machines also reschedule instructions and
data, and that broken thread code on even single-processor machines can
manifest its bugs, aren't you? In other words, that your short-sighted and
irresponsibly lazy idea won't even work reliably anyway?


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