On Wed, Aug 12, 2015 at 11:58 AM, Eliot Miranda eliot.miranda@gmail.com wrote:

On Wed, Aug 12, 2015 at 11:57 AM, tim Rowledge tim@rowledge.org wrote:

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On 12-08-2015, at 11:20 AM, Eliot Miranda eliot.miranda@gmail.com wrote:

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On Wed, Aug 12, 2015 at 11:09 AM, Levente Uzonyi leves@elte.hu wrote: I wonder if you're creating two forwarders in case of #become:, with

objects of different size, or just one forwarder for the larger object while copying the smaller object over the larger one (when possible).

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Right now it's the simplest thing that could possibly work. I think

this is a great idea though. It would potentially eliminate the post-become stack scan if all objects can be becomed either by exchanging contents or (in one-way) shortening. Alas I don't have time for this right now. Any volunteers interested?

Huh; I thought you had done that ages ago. I recall suggesting it really early in your spur work and could have sworn you did it right then.

I think I did exchange of contents when the objects are of the same size, at your prompting, but I definitely know I /didn't/ do shortening in one-way as per Levente's suggestion.

_,,,^..^,,,_

Note that there are a fair few potential cases to cover here. An object may be the last object in eden, or the survivor spaces and may have room beyond it to lengthen it, so it could become a larger object by stretching and copying. It may be in old space and followed by a free object and so again be amenable to stretching. I suggest that someone collect data on how often shrinking and/or stretching is an option before expending effort here.

_,,,^..^,,,_ best, Eliot