RFR (XXS): 8049051: Use of during_initial_mark_pause() in G1CollectorPolicy::record_collection_pause_end() prevents use of seperate object copy time prediction during marking
bengt.rutisson at oracle.com
Thu Jul 10 09:36:10 UTC 2014
On 2014-07-10 11:08, Thomas Schatzl wrote:
> Hi Bengt,
> thanks for the review. See below for my comments.
> On Tue, 2014-07-08 at 08:49 +0200, Bengt Rutisson wrote:
>> Hi Thomas,
>> On 2014-07-02 14:33, Thomas Schatzl wrote:
>>> Hi all,
>>> some apparent bug in the G1 pause time prediction logic: when ending
>>> an initial mark pause, G1 is supposed to switch to different predictors
>>> for the object copy time.
>>> Since the code that sets the flag to indicate to the prediction that the
>>> other predictor should be used for object copy time prediction wrongly
>>> reuses during_initial_mark_pause() that has been unconditionally set to
>>> false before, G1 never switches predictors.
>>> The fix is to use the backup ("last_pause_included_initial_mark") value
>>> for during_initial_mark_pause() already used in several places in that
>> The fix looks good.
>> One question.
>> Why do we need these local variables?
>> bool new_in_marking_window = _in_marking_window;
>> bool new_in_marking_window_im = false;
>> They are only used in one place further down to set the corresponding
>> instance variables:
>> _in_marking_window = new_in_marking_window;
>> _in_marking_window_im = new_in_marking_window_im;
>> Can't we just move the if (last_pause_included_initial_mark) check to
>> that place and skip the local variables?
> Yes, we can :)
> New webrev at
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