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

Tony Printezis Antonios.Printezis at sun.com
Tue Jul 7 11:23:28 PDT 2009


John Coomes wrote:
> Tony Printezis (Antonios.Printezis at Sun.COM) wrote:
>   
>> John,
>>
>> New output below. Looks good?
>>     
>
> Yes, I like it.
Cool.
>   One nit, though:  I would remove the trailing comma
> after the survivors size.
>   
Good catch, bad cut-and-paste! THanks.

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
>>>
>>>   
>>>       
>> -- 
>> ----------------------------------------------------------------------
>> | Tony Printezis, Staff Engineer    | Sun Microsystems Inc.          |
>> |                                   | MS BUR02-311                   |
>> | e-mail: tony.printezis at sun.com    | 35 Network Drive               |
>> | office: +1 781 442 0998 (x20998)  | Burlington, MA01803-0902, USA  |
>> ----------------------------------------------------------------------
>> e-mail client: Thunderbird (Solaris)
>>
>>
>>     
>
>   

-- 
---------------------------------------------------------------------
| Tony Printezis, Staff Engineer   | Sun Microsystems Inc.          |
|                                  | MS UBUR02-311                  |
| e-mail: tony.printezis at sun.com   | 35 Network Drive               |
| office: +1 781 442 0998 (x20998) | Burlington, MA 01803-2756, USA |
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