Code review request: 6855834: G1: minimize the output when -XX:+PrintHeapAtGC is set (S)

Tony Printezis Antonios.Printezis at sun.com
Tue Jul 7 10:53:11 PDT 2009


John,

New output below. Looks good?

Tony

--------------

{Heap before GC invocations=12 (full 3):
 garbage-first heap   total 26624K, used 22004K [0xf2400000, 0xf3e00000, 
0xf5400000)
  region size 1024K, 16 young (16384K), 2 survivors (2048K),
 compacting perm gen  total 16384K, used 3070K [0xf5400000, 0xf6400000, 
0xf9400000)
   the space 16384K,  18% used [0xf5400000, 0xf56ffa68, 0xf56ffc00, 
0xf6400000)
No shared spaces configured.
15.982: [GC pause (young) 21M->9990K(28M), 0.1216863 secs]
Heap after GC invocations=13 (full 3):
 garbage-first heap   total 28672K, used 9990K [0xf2400000, 0xf4000000, 
0xf5400000)
  region size 1024K, 4 young (4096K), 4 survivors (4096K),
 compacting perm gen  total 16384K, used 3070K [0xf5400000, 0xf6400000, 
0xf9400000)
   the space 16384K,  18% used [0xf5400000, 0xf56ffa68, 0xf56ffc00, 
0xf6400000)
No shared spaces configured.
}
{Heap before GC invocations=13 (full 3):
 garbage-first heap   total 28672K, used 21584K [0xf2400000, 0xf4000000, 
0xf5400000)
  region size 1024K, 16 young (16384K), 4 survivors (4096K),
 compacting perm gen  total 16384K, used 3077K [0xf5400000, 0xf6400000, 
0xf9400000)
   the space 16384K,  18% used [0xf5400000, 0xf57016b8, 0xf5701800, 
0xf6400000)
No shared spaces configured.
16.570: [Full GC (System.gc()) 21M->566K(24M), 0.1898490 secs]
Heap after GC invocations=14 (full 4):
 garbage-first heap   total 24576K, used 566K [0xf2400000, 0xf3c00000, 
0xf5400000)
  region size 1024K, 0 young (0K), 0 survivors (0K),
 compacting perm gen  total 16384K, used 3075K [0xf5400000, 0xf6400000, 
0xf9400000)
   the space 16384K,  18% used [0xf5400000, 0xf5700dd0, 0xf5700e00, 
0xf6400000)
No shared spaces configured.
}


John Coomes wrote:
> Tony Printezis (Antonios.Printezis at Sun.COM) wrote:
>   
>> http://cr.openjdk.java.net/~tonyp/6855834/webrev.0/
>>
>> The CR has more information on the new format:
>>     
>
> Haven't reviewed the code yet (sorry), but have some questions.
>
> Does G1 have reasonably accurate occupancy info when this info is
> printed?  If so, it would be nice to have a breakdown of the amount or
> percentage used in young regions, survivor regions & old regions.
> That would be closer to the info you get for the other collectors.
>
> If not, then I would combine the "region size" line with the one that
> follows it.  Best shown by example:
>
> Change this:
>
>  garbage-first heap   total 24576K, used 16950K [0xf2400000, 0xf3c00000, 0xf5400000)
>   region size 1024K
>   young regions 16 / 16384K  survivor regions 0 / 0K
>
>
> To something like this:
>
>  garbage-first heap   total 24576K, used 16950K [0xf2400000, 0xf3c00000, 0xf5400000)
>   region size 1024K, 16 young (16384K), 1 survivor (1024K)
>
> -John
>
>   

-- 
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| Tony Printezis, Staff Engineer    | Sun Microsystems Inc.          |
|                                   | MS BUR02-311                   |
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