compatibility issue regarding the active processor count

David Holmes - Sun Microsystems David.Holmes at Sun.COM
Wed Oct 1 02:13:32 PDT 2008

My 2c: fix it and add a flag to restore the incorrect behaviour.

David Holmes

Xiaobin Lu said the following on 10/01/08 10:11:
> 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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