Request for review 8024366: UseNUMAInterleaving should be available for other GC's.

Srinivas Ramakrishna ysr1729 at
Fri Sep 6 12:47:35 PDT 2013

Hi Jon, Shrinivas --

I think the comment might be better if it were reframed for the case
when UseNUMA is not set since the comment occurs in the else arm of
the test.
That makes it clearer what the code's intention is. (Given the default
settings on Linux and Solaris, that section of code is essentially a
no-op on
Solaris and Linux.

For example:

3655   } else {
3656     // NUMA interleaving (numa_global) is ON by default on Windows,
3657    // and OFF by default on Linux and Solaris.
3658     // If UseNUMA is not set, we disable interleaving on Windows,
3659     // unless it's explicitly set on the command-line.
3661     if (FLAG_IS_DEFAULT(UseNUMAInterleaving)) {
3662       FLAG_SET_ERGO(bool, UseNUMAInterleaving, false);
3663     }
3664   }

Where is the reason for the difference in Windows settings documented? What was
the reason for turning it off on Windows when UseNUMA is not set?  Naively, I'd
have thought that UseNUMAInterleaving would not matter when UseNUMA isn't set.
(I have not kept up with the changes here, and don't have the code
handy to have a look,
but i wanted to get these comments out before i forgot about it.)
Sorry that this isn't a real
review :-)

-- ramki

On Fri, Sep 6, 2013 at 7:36 AM, Jon Masamitsu <jon.masamitsu at> wrote:
> UseNUMA is implemented for the UseParallelGC.  For other GC's this change
> makes the interleaving option UseNUMAInterleaving available.
> This patch was contributed by Shrinivas Joshi.

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