Le 06/06/2010 00:45, Martin Buchholz a écrit :
Thanks to all the reviewers who were too polite to say:
"""What was Martin thinking?"""
For some reason I had imagined that Math.random()
was itself synchronized.
After editing, I have a very small change that is hardly worth doing
except that I already have a webrev.
http://cr.openjdk.java.net/~martin/webrevs/openjdk7/Math.random/
Martin
I think initRG can be written like that:
private static synchronized Random initRNG() {
RandomrandomNumberGenerator = this.randomNumberGenerator;
return (randomNumberGenerator == null)? this.randomNumberGenerator = new
Random() :randomNumberGenerator;
}
Rémi
On Sat, Jun 5, 2010 at 07:00, Eamonn McManus<eamonn.mcma...@sun.com> wrote:
It seems to me that if two threads call this Math.random() at the same time
then two instances of Random() can be constructed. That contradicts the
specification of the method, and is theoretically observable because the two
values from Math.random() will typically not be a pair of values that could
have been returned from consecutive calls to nextDouble() on a single Random
instance. Granted, the chances of this actually mattering are infinitesimal,
but I think the performance gain of avoiding a synchronized method only on
the very first call to Math.random() is infinitesimal too. So I'd be
inclined to leave well enough alone here.
Eamonn
Martin Buchholz wrote:
Here's an optimization for Math.random() that appears to be safe,
despite the double-check access:
http://cr.openjdk.java.net/~martin/webrevs/openjdk7/Math.random/
David, if you agree, could you file a bug?
Thanks,
Martin
