On Jan 10 2014, at 05:42 , Paul Sandoz <paul.san...@oracle.com> wrote:
> Hi, > > Some tweaks to the Stream forEachOrdered operation: > > http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8029452-ForEachOrdered/webrev/ > > The first tweak is to size the CHM used in ForEachOrderedTask, this avoids > concurrent resizes and the costs associated with those. +1 > > The second tweak is to consolidate the reporting of elements to within the > ForEachOrderedTask.tryComplete method. > > I have also removed the inconsistently applied synchronized block. Either we > apply it consistently to reporting or not at all. It was originally there > because we were not sure that the "happens-before" relationship [1] between > elements would be guaranteed. However, ForEachOrderedTask sets up such a > relationship via completion counts to ensure leaf nodes complete in encounter > order (if any) where only one leaf can be completing (which was left most > leaf that was not completed), hence stamping a fence in the ground at these > point seems redundant (at least i cannot see its value but could be missing > something subtle). Coud not the lock object be removed? Mike > > Paul. > > [1] > * <p>This operation processes the elements one at a time, in encounter > * order if one exists. Performing the action for one element > * <a > href="../concurrent/package-summary.html#MemoryVisibility"><i>happens-before</i></a> > * performing the action for subsequent elements, but for any given > element, > * the action may be performed in whatever thread the library chooses. > * > * @param action a <a href="package-summary.html#NonInterference"> > * non-interfering</a> action to perform on the elements > * @see #forEach(Consumer) > */ > void forEachOrdered(Consumer<? super T> action); >
