[concurrency-interest] Atomic assignment

Gregg Wonderly gregg at cytetech.com
Fri May 8 11:02:48 EDT 2009


Okay, it we actually just have the ++/-- not atomic issue, than I am okay with 
that because I don't suddenly have new, broken code.  I looked around some more 
and ran the test code on that old issue on my dual core laptop and saw no 
failures.  But, I'm not sure after looking at that code whether it actually 
makes modifications in a way that would show a problem.

Gregg Wonderly

Sam Berlin wrote:
> My interpretation is that the scenario today is that a volatile 
> long/double is atomic.  A non-volatile long/double is not atomic.  And 
> the RFE that was closed as will-not-fix was asking for all access to 
> long/double (even non-volatile) to be atomic.
> 
> Sam
> 
> On Fri, May 8, 2009 at 10:27 AM, Gregg Wonderly <gregg at cytetech.com 
> <mailto:gregg at cytetech.com>> wrote:
> 
>     So will the compiler be changed to not allow volatile to exist on
>     double/long declarations since it does not work?  Or might there be
>     a warning that volatile does not produce atomic results on all
>     statements that assign to or reference a double/long value?
> 
>     Sigh...
> 
>     Gregg Wonderly
> 
> 
>     David Holmes wrote:
> 
>         Hi Mark,
> 
>         That bug is (or became) a RFE for the spec to make all accesses to
>         double/long atomic and that is not going to happen hence the
>         "will not fix".
>         There are a number of other bugs that pertain to atomic access
>         to volatile
>         long/double eg: 4247780 which was fixed back in 1.2.2
> 
>         Thanks
>         David Holmes
> 
>             -----Original Message-----
>             From: concurrency-interest-bounces at cs.oswego.edu
>             <mailto:concurrency-interest-bounces at cs.oswego.edu>
>             [mailto:concurrency-interest-bounces at cs.oswego.edu
>             <mailto:concurrency-interest-bounces at cs.oswego.edu>]On
>             Behalf Of Mark
>             Thornton
>             Sent: Friday, 8 May 2009 7:29 AM
>             To: concurrency-interest at cs.oswego.edu
>             <mailto:concurrency-interest at cs.oswego.edu>
>             Subject: [concurrency-interest] Atomic assignment
> 
> 
> 
>             I was sure that the problem of (non)atomic assignment to
>             volatile longs
>             and doubles had been fixed, but this bug report suggests
>             otherwise:
> 
>             http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4023233
> 
>             Anyone know for sure?
> 
>             Mark Thornton
> 
>             _______________________________________________
>             Concurrency-interest mailing list
>             Concurrency-interest at cs.oswego.edu
>             <mailto:Concurrency-interest at cs.oswego.edu>
>             http://cs.oswego.edu/mailman/listinfo/concurrency-interest
> 
> 
> 
>         _______________________________________________
>         Concurrency-interest mailing list
>         Concurrency-interest at cs.oswego.edu
>         <mailto:Concurrency-interest at cs.oswego.edu>
>         http://cs.oswego.edu/mailman/listinfo/concurrency-interest
> 
> 
> 
>     _______________________________________________
>     Concurrency-interest mailing list
>     Concurrency-interest at cs.oswego.edu
>     <mailto:Concurrency-interest at cs.oswego.edu>
>     http://cs.oswego.edu/mailman/listinfo/concurrency-interest
> 
> 



More information about the Concurrency-interest mailing list