RFR(M) 8043575: Dynamically parallelize reference processing work

[Thomas Schatzl]

Hi all,

  after some talk about making parallel ref processing default for G1
the suggestion came up to extract that part into a separate CR. I will
post that one shortly.

However, this means that there is a trivial change in this webrev to be
looked at:

http://cr.openjdk.java.net/~tschatzl/8043575/webrev.3_to_4 (diff)
http://cr.openjdk.java.net/~tschatzl/8043575/webrev.4 (full)

This is the full change, for reference:

--- old/src/hotspot/share/gc/g1/g1Arguments.cpp	2018-06-14
13:30:08.166027425 +0200
+++ new/src/hotspot/share/gc/g1/g1Arguments.cpp	2018-06-14
13:30:07.818016510 +0200
@@ -122,10 +122,6 @@
     FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
   }
 
-  if (FLAG_IS_DEFAULT(ParallelRefProcEnabled) && ParallelGCThreads >
1) {
-    FLAG_SET_DEFAULT(ParallelRefProcEnabled, true);
-  }
-
   log_trace(gc)("MarkStackSize: %uk  MarkStackSizeMax: %uk", (unsigned
int) (MarkStackSize / K), (uint) (MarkStackSizeMax / K));
 
   // By default do not let the target stack size to be more than 1/4
of the entries

Thanks,
  Thomas

On Thu, 2018-06-14 at 09:41 +0200, Thomas Schatzl wrote:
> Hi Kim and Sangheon,
> 
> On Wed, 2018-06-13 at 18:05 -0400, Kim Barrett wrote:
> > > On Jun 8, 2018, at 10:52 AM, Thomas Schatzl <thomas.schatzl at oracl
> > > e.
> > > com> wrote:
> > > 
> > > Webrev is at http://cr.openjdk.java.net/~tschatzl/8043575/webrev.
> > > 3/
> > >  .
> > > 
> > > This webrev is based on top of latest jdk/jdk and
> > > https://bugs.openjdk.java.net/browse/JDK-8202845 .
> > > 
> > > If you want to test parallel gc, you also need the fixes for JDK-
> > > 8204617 and JDK-8204618 currently out for review.
> > > 
> > > Testing:
> > > hs-tier1-4,jdk-tier1-3 with +/-ParallelRefProcEnabled
> > > 
> > > Thanks,
> > >  Thomas
> > 
> > Looks good.
> > 
> 
>   thanks for your reviews.
> 
> Thomas
>