# About php6 gc

- Thread: https://externals.io/message/45985
- Original archive: https://news-web.php.net/php.internals/45985
- Started by Mathieu Suen on 2009-11-10T08:21:11+00:00
- Messages: 2
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## #45985 — Mathieu Suen — 2009-11-10T08:21:11+00:00

URL: https://externals.io/message/45985#45985

Hi,

By looking at the php6 gc I guess you introduce  a mark and sweep gc.
Looking at the *_root function, it also seems that you have a 
generational mark & sweep gc.

I have a couple of question :

How many generation do you have?

What is the meaning of the different color (black, white, grey)?

Thanks

-mthk

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## #45995 — Derick Rethans — 2009-11-10T17:31:25+00:00

URL: https://externals.io/message/45985#45995 · In reply to: #45985

> By looking at the php6 gc I guess you introduce  a mark and sweep gc.
> Looking at the *_root function, it also seems that you have a generational
> mark & sweep gc.
> 
> I have a couple of question :
> 
> How many generation do you have?
> 
> What is the meaning of the different color (black, white, grey)?

The synchronous collection mechanism from  following paper is 
implemented (and an explanation upon how it works with PHP is making it 
into the manual soon):

http://www.research.ibm.com/people/d/dfb/papers/Bacon01Concurrent.pdf

This is also in PHP 5.3 though.

Derick

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