From 32b2aa918360bbeb500604ae8623833e9e068c87 Mon Sep 17 00:00:00 2001 From: Aleksey Shipilev Date: Tue, 25 Jun 2013 20:06:09 +0100 Subject: [PATCH] 8014233: java.lang.Thread should have @Contended on TLR fields Add the @Contended over three TLR fields. Reviewed-by: psandoz, chegar, dholmes, dl --- jdk/src/share/classes/java/lang/Thread.java | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/jdk/src/share/classes/java/lang/Thread.java b/jdk/src/share/classes/java/lang/Thread.java index bb175ff89ad..eb89670d149 100644 --- a/jdk/src/share/classes/java/lang/Thread.java +++ b/jdk/src/share/classes/java/lang/Thread.java @@ -1993,12 +1993,21 @@ class Thread implements Runnable { // The following three initially uninitialized fields are exclusively - // managed by class java.util.concurrent.ThreadLocalRandom. + // managed by class java.util.concurrent.ThreadLocalRandom. These + // fields are used to build the high-performance PRNGs in the + // concurrent code, and we can not risk accidental false sharing. + // Hence, the fields are isolated with @Contended. + /** The current seed for a ThreadLocalRandom */ + @sun.misc.Contended("tlr") long threadLocalRandomSeed; + /** Probe hash value; nonzero if threadLocalRandomSeed initialized */ + @sun.misc.Contended("tlr") int threadLocalRandomProbe; + /** Secondary seed isolated from public ThreadLocalRandom sequence */ + @sun.misc.Contended("tlr") int threadLocalRandomSecondarySeed; /* Some private helper methods */