Call for Discussion: New Project: Lilliput
rkennke at redhat.com
Fri Mar 12 22:50:10 UTC 2021
>> I would propose myself as the project lead for Lilliput. :-)
>> For initial committers I think we need all expertise in runtime and GC
>> that we can get. From the top of my head I’m thinking of John Rose,
>> Dave Dice, Andrew Dinn, Andrew Haley, Erik Österlund, Aleksey
>> Shipilev, Coleen Phillimore, Stefan Karlsson, Per Liden. Please
>> suggest anybody who you think should be involved in this too. (Or
>> yourself if you want to be in, or if you have no interest in it.)
> Yes, please. I'd like to be a committer.
> I had done experiments with a
> klass pointer indirection, which could effectively be a klass index.
I had a little exchange with Thomas Stuefe, and we believe we can split
Klass into fixed-sized part, and variable-sized part, have the
fixed-size base reference the variable-sized part. Then we can allocate
the fixed Klass instances into a 'flat' array in a contiguous memory
region, and with some smart placement and aligmment we can use a
compressed pointer to address it, which will effectively be an index
into that array. Which means that with N bits of
compressed-class-pointer we could address 2^N Klasses :-) No indirection
needed if done so afaict.
But hey, let's get the project off the ground asap, and have technical
discussions there, yes? :-)
> In JDK 18, we're going to be removing BiasedLocking so that removes one
> use of the markWord.
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