Review Request: UseNUMAInterleaving

Y. S. Ramakrishna y.s.ramakrishna at
Tue Aug 16 14:31:14 PDT 2011

Not answering for Igor here (and i have not looked at yr
webrev; just responding to the content of the email messages),
but this question came up briefly at lunch today ....

On 08/16/11 13:14, Deneau, Tom wrote:
> Are you saying that in the future numa_local will be supported on
> Windows, and that even then it might still be advantageous to have a
> flag (UseNUMAInterleaving) which instead maps all the regions to
> numa_global?  Should this flag be available on all OSes?

... and, FWIW, in my opinion, it would seem to be be advantageous
and also less confusing to support the same semantics (num_global) when
+UseNUMAInterleaving, uniformly on all OS's, rather than
restrict that semantics to just windows. (And yes support
that flag even after we extend our implementation to do numa_local
on windows in the future...)

- ramki

> -- Tom
>> -----Original Message-----
>> From: Igor Veresov [mailto:igor.veresov at]
>> Sent: Monday, August 08, 2011 1:43 PM
>> To: hotspot-gc-dev at; Deneau, Tom
>> Subject: Re: Review Request: UseNUMAInterleaving
>> Hi, Tom!
>> Sorry it took me so long to get to that.
>> 1. I don't think the new version of flag usage is prudent. The reason I
>> proposed to introduce a new flag for interleaving is that it would make
>> life easier in the future when the proper NUMA-aware implementation of
>> GCs are added (G1 would be the most probable candidate). I would propose
>> to still have UseNUMAInterleaving flag.
>> The usage would be as follows:
>> - If UseNUMA is specified on Windows that would turn UseNUMAInterleaving
>> (for the time being, and that behavior would change in the future).
>> - If UseNUMAInterleaving is specified on the command line, you just do
>> the interleaving. If you don't add this flag now, you'll have to do that
>> anyway as soon as NUMA-aware GCs start supporting windows.
>> igor
>> On 5/26/11 4:37 PM, Deneau, Tom wrote:
>>> I have incorporated the change suggested by Paul Hohensee to just use
>> the existing UseNUMA flag rather than introduce a new flag.  Please let me
>> know when you think this will be able to be checked in...
>>> The new webrev is at
>>> -- Tom Deneau, AMD

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