From: "sam.saffron (Sam Saffron)" <sam.saffron@...>
Date: 2013-10-09T07:04:27+09:00
Subject: [ruby-core:57746] [ruby-trunk - Bug #8984]	ObjectSpace.memsize_of(obj) should return with sizeof(RVALUE)


Issue #8984 has been updated by sam.saffron (Sam Saffron).


Personally I have only ever seen mention of this in http://stackoverflow.com/questions/10068018/memory-size-of-a-hash-or-other-object

I googled pretty hard and all I saw was wonderful pictures of tenderlove and a slightly less accurate description here: http://www.slideshare.net/tenderlove/hidden-gems-of-ruby-19 http://imgur.com/yeFYtiM

I think we should break compatibility here and properly document, cause people just have no idea about this now
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Bug #8984: ObjectSpace.memsize_of(obj) should return with sizeof(RVALUE)
https://bugs.ruby-lang.org/issues/8984#change-42349

Author: ko1 (Koichi Sasada)
Status: Assigned
Priority: Normal
Assignee: ko1 (Koichi Sasada)
Category: ext
Target version: current: 2.1.0
ruby -v: -
Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN


Now, ObjectSpace.memsize_of(obj) return without sizeof(RVALUE).
For example, ObjectSpace.memsize_of('foo') returns 0 because shorter string are embedded in RVALUE.

Proposal is returning the size including sizeof(RVALUE).
If we introduce variable RVALUE size (*1), then it will help.

*1: for example, T_FLOAT only use sizeof(double).
    Only 2 words (or 1 word on 64bit enviornment) are needed.


Question is: it breaks compatibility, but anyone care about it?

Another option is to add optional parameter. memsize_of(obj, include_rvalue: true), etc.




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