Review Request: UseNUMAInterleaving

Y. S. Ramakrishna y.s.ramakrishna at oracle.com
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 oracle.com]
>> Sent: Monday, August 08, 2011 1:43 PM
>> To: hotspot-gc-dev at openjdk.java.net; 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
>>> http://cr.openjdk.java.net/~tdeneau/UseNUMAInterleaving/webrev.02/
>>>
>>> -- Tom Deneau, AMD
>>>
>>>
> 


More information about the hotspot-gc-dev mailing list