[jira] Created: (HARMONY-5947) NOS size can go up and down even gc.nos_size command option is set.

["li, shisheng (JIRA)" <ji...@apache.org>]

NOS size can go up and down even gc.nos_size command option is set.
-------------------------------------------------------------------

                 Key: HARMONY-5947
                 URL: https://issues.apache.org/jira/browse/HARMONY-5947
             Project: Harmony
          Issue Type: Bug
          Components: DRLVM
    Affects Versions: 5.0M6
         Environment: All
            Reporter: li, shisheng


With this bug, even you specify nos_size command options, the real NOS size
will still go up and down. That option is expected to really fix the size of NOS.

To reproduce the bug, you need  to firstly write a simple hello world program
which will alloc much data in both NOS and LOS. Here is one example.

import java.io.*;
import java.util.*;


public class Hello {

	public static void main(String[] args)
	{
		Object o = null;
		Object[] os = null;
		
		while(true)
		{
			o = new Object();
			os = new Object[100 * 1024];
		}
	}
}


And then try a command like this:

java -Xms512m -Xmx512m -verbose:gc -XX:gc.nos_size=8M -XX:gc.minor_algorithm=PARTIAL_FORWARD -jar hello.jar

Here with gc verbose, you can get the NOS size easily.

With the command above, in my system, the NOS size go up to 117M firstly and then go down to 3M, then get stable.

One source of this bug is in file: los\lspace_alloc_collect.cpp, function:lspace_reset_for_slide ,
which is called when los collection. 


-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.