Difference between revisions of "Versus the garbage collector"

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(Two links about Boehm GC were dead, substituted with what I could find)
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* http://forum.dlang.org/post/bsqqfmhgzntryyaqrtky@forum.dlang.org
 
* http://forum.dlang.org/post/bsqqfmhgzntryyaqrtky@forum.dlang.org
 
* http://forum.dlang.org/post/l34lei$255v$1@digitalmars.com
 
* http://forum.dlang.org/post/l34lei$255v$1@digitalmars.com
* http://www.hpl.hp.com/personal/Hans_Boehm/gc/issues.html (About the Boehm GC, but generally interesting)
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* ftp://ftp.sgi.com/other/gc/issues.html (About the Boehm GC, but generally interesting)
* http://www.hpl.hp.com/personal/Hans_Boehm/popl04/refcnt.pdf The Space Cost of Lazy Reference Counting (talk slides)
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* http://www.hpl.hp.com/techreports/2003/HPL-2003-215.html The Space Cost of Lazy Reference Counting (technical report)
 
* http://www.quora.com/Computer-Programming/How-do-reference-counting-and-garbage-collection-compare/answer/Jon-Harrop-1?srid=3Gvg&share=1 Jon Harrop's answer to: Computer Programming: How do reference counting and garbage collection compare?
 
* http://www.quora.com/Computer-Programming/How-do-reference-counting-and-garbage-collection-compare/answer/Jon-Harrop-1?srid=3Gvg&share=1 Jon Harrop's answer to: Computer Programming: How do reference counting and garbage collection compare?

Revision as of 09:45, 10 July 2014

The big discussion about the garbage collector repeatedly comes up. This page tries to provide a summary.


Why GC is bad

  • Unpredictable pauses which stop the world
  • Current implementation sucks

Why GC is good

  • Safe by default and non-leaking memory management
  • Acceptable performance for many cases
  • Supports immutable types

Common Ground

  • We want something, which is safe by default

Proposals

Compiler-supported Reference Counting

Compiler generates reference counting for all references

  • Pro: More predictable
  • Pro: No manual rewriting necessary
  • Contra: Cycles would leak
  • Contra: Overhead due to inc/dec operations
  • Open question: Does ARC guarantee memory safety?

Library Reference Counting

Use std.typecons.RefCounted

  • Pro: Garbage collector still provides safety
  • Contra: Lots of manual work
  • Contra: Overhead due to inc/dec operations

DIP18: nogc attribute

  • Pro: Compile-time checked
  • Pro: Selective usage
  • Contra: Attribute creep

Implement Certain Interface

  • Cannot find original thread

Links