What influences young generation pause times?

Y. Srinivas Ramakrishna y.s.ramakrishna at oracle.com
Thu Apr 22 12:35:09 PDT 2010


Raman,

FWIW, it appears to me that all of the action here is really at
the core libraries level (including System.gc()), except at
the point at which it interacts with the current semantics
of the vm option DisableExplicitGC (which should really become a
default global property spec rather than a JVM flag at
that point). So, to me at least, it appears reasonable that this
proposal start with the appropriate core-libraries
sponsor. Interactions with existing vm options, jconsole, jmap
and mbean controls etc. will need to be worked out in
concert with the core libs (sponsors), the serviceability
team and the gc team as the spec for this is crystallized.

my $0.02.
-- ramki

On 04/22/10 09:24, Raman Gupta wrote:
> On 04/22/2010 02:22 AM, Jon Masamitsu wrote:
>> On 4/21/10 4:19 PM, Raman Gupta wrote:
>>> I am not suggesting any new API at this time -- I mentioned it only as
>>> a pie-in-the-sky kind of thing.
>>>
>>> My current suggestion is simply to gate System.gc() (or actually
>>> Runtime.gc() I guess) with a new RuntimePermission. Without the
>>> appropriate permission granted, gc() would simply be a no-op.
>>
>> I know very little about RuntimePermission. Who needs to be involved in
>> creating
>> a new one?
> 
> It seems the core libraries group is responsible for anything in 
> java.lang, which both SecurityManager and RuntimePermission are:
> 
> http://openjdk.java.net/groups/core-libs/
> 
> So presumably both the GC group and the core libraries group would have 
> to be ok with this change. If you guys are ok with this in principle, I 
> can coordinate getting approval from the core-libs group via their 
> mailing list. I would also need a sponsor -- I don't know if they would 
> be from gc-dev or core-libs or both.
> 
> Documentation like this one would have to be updated as well -- if this 
> is part of the JDK source then that is easy enough:
> 
> http://java.sun.com/javase/6/docs/technotes/guides/security/permissions.html 
> 
> 
> Cheers,
> Raman



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