Packed Objects (original) (raw)

Daniel Hicks danhicks at ieee.org
Sat Nov 24 12:38:25 PST 2012

Just as an aside, the "Classic" JVM on IBM iSeries was doing a primitive form of packed objects (only for system objects) years ago. For classes in the system classpath there was an attribute that could specify the offsets of individual fields, allowing "native" data structures to be accessed directly from Java code.

On 11/24/2012 2:00 PM, hotspot-dev-request at openjdk.java.net wrote:

Send hotspot-dev mailing list submissions to hotspot-dev at openjdk.java.net > To subscribe or unsubscribe via the World Wide Web, visit http://mail.openjdk.java.net/mailman/listinfo/hotspot-dev or, via email, send a message with subject or body 'help' to hotspot-dev-request at openjdk.java.net > You can reach the person managing the list at hotspot-dev-owner at openjdk.java.net > When replying, please edit your Subject line so it is more specific than "Re: Contents of hotspot-dev digest..." >> Today's Topics: > 1. PackedObjects (Doug Lea) 2. Re: [concurrency-interest] RFR (S): JEP-142: Reduce Cache Contention on Specified Fields (Aleksey Shipilev) 3. Re: RFR (S): JEP-142: Reduce Cache Contention on Specified Fields (Aleksey Shipilev) 4. Re: RFR (S): JEP-142: Reduce Cache Contention on Specified Fields (Michael Barker) 5. Re: RFR (S): JEP-142: Reduce Cache Contention on Specified Fields (Aleksey Shipilev) >> ---------------------------------------------------------------------- > Message: 1 Date: Fri, 23 Nov 2012 15:00:29 -0500 From: Doug Lea <dl at cs.oswego.edu> Subject: PackedObjects To: hotspot-dev at openjdk.java.net Message-ID: <50AFD5DD.2000804 at cs.oswego.edu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed >> On the occasion of subscribing to this list for the sake of exchanges about @Contended, I figure that it is also worth alerting folks who haven't heard about IBM's PackedObject proposal that they now have released some slides etc at > http://www.slideshare.net/mmitran/ibm-java-packed-objects-mmit-20121120 > This is a VM-level approach to supporting value/struct/tuple types, that I hope catches on and turns into a JEP. Of all the ways to do this sort of thing, it strikes me as being among the few that might possibly succeed (and actually has succeeded at least to the point of a J9 implementation). > -Doug

Dan Hicks Experience is the name everyone gives for their mistakes. --Oscar Wilde

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