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
Tue Jul 8 06:49:44 UTC 2014
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.
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
_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?
More information about the hotspot-gc-dev