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8061553: Contended Locking fast enter bucket

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JEP-143/JDK-8061553 Contended Locking fast enter bucket

Co-authored-by: Dave Dice <dave.dice@oracle.com>
Co-authored-by: Karen Kinnear <karen.kinnear@oracle.com>
Reviewed-by: dholmes, acorn
This commit is contained in:
Daniel D. Daugherty 2015-02-13 10:01:42 -08:00
parent 3d3f6553c0
commit a9e28164eb
6 changed files with 96 additions and 54 deletions
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16
hotspot/src/cpu/sparc/vm/macroAssembler_sparc.cpp
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@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -2943,24 +2943,14 @@ void MacroAssembler::compiler_lock_object(Register Roop, Register Rmark,
}
bind (IsInflated);
if (EmitSync & 64) {
// If m->owner != null goto IsLocked
// Test-and-CAS vs CAS
// Pessimistic form avoids futile (doomed) CAS attempts
// The optimistic form avoids RTS->RTO cache line upgrades.
ld_ptr(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner), Rscratch);
andcc(Rscratch, Rscratch, G0);
brx(Assembler::notZero, false, Assembler::pn, done);
delayed()->nop();
// m->owner == null : it's unlocked.
}
// Try to CAS m->owner from null to Self
// Invariant: if we acquire the lock then _recursions should be 0.
add(Rmark, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner), Rmark);
mov(G2_thread, Rscratch);
cas_ptr(Rmark, G0, Rscratch);
cmp(Rscratch, G0);
andcc(Rscratch, Rscratch, G0); // set ICCs for done: icc.zf iff success
// set icc.zf : 1=success 0=failure
// ST box->displaced_header = NonZero.
// Any non-zero value suffices:
// markOopDesc::unused_mark(), G2_thread, RBox, RScratch, rsp, etc.