RFR (S): 8008737: The trace event vm/gc/heap/summary is missing for CMS
mikael.gerdin at oracle.com
Tue Mar 26 03:25:55 PDT 2013
On 2013-03-26 11:19, Erik Helin wrote:
> 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:
This looks good to me.
> On 03/13/2013 07:35 PM, Erik Helin wrote:
>> 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
>> 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:
>> 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
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