compatibility issue regarding the active processor count

Daniel D. Daugherty Daniel.Daugherty at Sun.COM
Wed Oct 1 06:32:48 PDT 2008

The default should be the correct behavior and the option should
restore the previous incorrect behavior. The hard part will be
naming the option. Perhaps:


The description could be something like:

    Restore incorrect active processor count algorithm for
    backward compatibility.

Just suggestions...


Xiaobin Lu wrote:
> Hi folks,
> I need your opinion about what we should do to solve the compatibility 
> issue regarding the active processor count. Basically, the problem is 
> on Solaris, if you create a processor set and then launch java process 
> without binding to that processor set, the number of available 
> processors to that java process is the total number of the online 
> processors minus the number of processors in the processor set you 
> created. Currently, we just report the total number of the online 
> processors as the active processor count which is wrong. This makes 
> the parallel garbage collector to behave in the wrong way (see bug 
> 6749430 for details) and we need to fix it per request from CBOE.
> There may be a compatibility issue after we correct this wrong 
> behavior when someone has already depended on this wrong return, which 
> we think it might be rare. We definitely need to invent a new flag in 
> order to address this and the question is whether we should keep the 
> current behavior as default or not. Personally, I feel we should have 
> that flag to fall back to the current wrong behavior, but I might be 
> wrong.
> Thanks so much in advance for your opinion.
> -Xiaobin

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