What influences young generation pause times?

Jon Masamitsu jon.masamitsu at oracle.com
Wed Apr 21 15:12:22 PDT 2010


There is no shortage of good ideas for the GC team to work on.
RuntimePermission might be another one, but the simple fact is
that we don't have time to work on everything we should.  Right
now our top priorities are reliability, faster GC's and more
predictable GC's.  Anything else is a hard sell.


On 04/20/10 14:53, Raman Gupta wrote:
> On 04/20/2010 02:11 PM, Tony Printezis wrote:
>> Additionally, I would be willing to bet money that if we provided such
>> an API, library writers will abuse it thinking that "hey, the end of
>> this library call will be a great time to do a young GC!", without
>> taking into consideration that many other threads could be doing
>> something totally different at the same time (we've seen way too many
>> libraries that call System.gc() already...).
> While I wasn't talking about young GC's, a couple of years ago I 
> submitted a proposal to to this list to add a new RuntimePermission 
> that would allow execution of explicit GCs [1]. Without such 
> permission, the System.gc() call would simply return without doing 
> anything. Ideally the signature would be modified to return a boolean 
> "true if performed", "false if not", and even more ideally, a more 
> comprehensive GC API could be provided.
> Such an approach would allow the addition of some explicit GC control 
> from applications, without allowing abuse by random libraries.
> While a couple of people chimed in that they too would like some 
> explicit GC control, the proposal was ignored.
> [1] http://markmail.org/message/cpmpwoodbcmspesc
> I'd at least like to hear some reasons why something like this can't 
> be done or isn't a good idea. I think it would be a great feature for 
> many people.
> Cheers,
> Raman

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