RFR (S): 8008737: The trace event vm/gc/heap/summary is missing for CMS

Bengt Rutisson bengt.rutisson at oracle.com
Tue Mar 26 03:30:32 PDT 2013


On 3/26/13 11:25 AM, Mikael Gerdin wrote:
> Erik,
>
> On 2013-03-26 11:19, Erik Helin wrote:
>> All,
>>
>> I have updated the change based on internal feedback.
>>
>> The changes between webrev.02 and webrev.03 are:
>> - Removed an unnecessary call to save_heap_summary in Initial_Mark.
>> - The reporting and saving of heap summary events has been split into
>>    two functions: save_heap_summary and report_heap_summary.
>>
>> New webrev located at:
>> http://cr.openjdk.java.net/~ehelin/8008737/webrev.03/
>
> This looks good to me.

Looks good to me too.

Bengt

>
> /Mikael
>
>>
>> Thanks,
>> Erik
>>
>> On 03/13/2013 07:35 PM, Erik Helin wrote:
>>> All,
>>>
>>> the previous two changes, webrev.00 and webrev.01, did not ensure that
>>> CMS collector had the heap lock when the call to capacity was being
>>> done. This did not cause any error during testing, but it could lead to
>>> strange bugs. I have therefore updated the change to take this into
>>> account.
>>>
>>> The new change, webrev.02, ensures that the heap summary data is only
>>> saved when the concurrent CMS collector has the heap lock. Since
>>> "collect_in_background" can be aborted for various reasons, the heap
>>> statistics are saved at three places for a concurrent CMS collection:
>>> 1. Initial mark
>>> 2. Final remark
>>> 3. Resizing
>>>
>>> The heap summary that will be sent for a concurrent CMS collection
>>> depend on how much progress the CMS background collector has done, the
>>> most recent one will always be sent.
>>>
>>> The same is being done for a foreground CMS collection, but then it is
>>> guaranteed that the heap summary will always be from the last save
>>> point, Resizing, since a foreground CMS collection can not be aborted.
>>>
>>> Please see the new webrev located at:
>>> http://cr.openjdk.java.net/~ehelin/8008737/webrev.02/
>>>
>>> Thanks,
>>> Erik
>>>
>>> On 02/24/2013 10:40 AM, Erik Helin wrote:
>>>> Hi all,
>>>>
>>>> this change adds the trace event vm/gc/heap/summary to the CMS
>>>> collector.
>>>>
>>>> Webrev:
>>>> http://cr.openjdk.java.net/~ehelin/8008737/webrev.00/
>>>>
>>>> Bug:
>>>> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8008737
>>>>
>>>> Testing:
>>>> JPRT
>>>>
>>>> Thanks,
>>>> Erik
>>>
>>



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