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8049737: Contended Locking reorder and cache line bucket

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JEP-143/JDK-8046133 - optimization #1 - reorder and cache line bucket.

Co-authored-by: Dave Dice <dave.dice@oracle.com>
Co-authored-by: Karen Kinnear <karen.kinnear@oracle.com>
Reviewed-by: shade, dice, dholmes, dsimms
This commit is contained in:
Daniel D. Daugherty 2014-10-14 10:32:12 -07:00
parent 51866388d1
commit f1ab0fae73
13 changed files with 302 additions and 247 deletions
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43
hotspot/src/share/vm/runtime/objectMonitor.cpp
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@ -257,7 +257,6 @@ bool ObjectMonitor::try_enter(Thread* THREAD) {
assert(_recursions == 0, "internal state error");
_owner = THREAD;
_recursions = 1;
OwnerIsThread = 1;
return true;
}
if (Atomic::cmpxchg_ptr (THREAD, &_owner, NULL) != NULL) {
@ -280,7 +279,6 @@ void NOINLINE ObjectMonitor::enter(TRAPS) {
// Either ASSERT _recursions == 0 or explicitly set _recursions = 0.
assert(_recursions == 0, "invariant");
assert(_owner == Self, "invariant");
// CONSIDER: set or assert OwnerIsThread == 1
return;
}
@ -296,7 +294,6 @@ void NOINLINE ObjectMonitor::enter(TRAPS) {
// Commute owner from a thread-specific on-stack BasicLockObject address to
// a full-fledged "Thread *".
_owner = Self;
OwnerIsThread = 1;
return;
}
@ -328,7 +325,7 @@ void NOINLINE ObjectMonitor::enter(TRAPS) {
// Prevent deflation at STW-time. See deflate_idle_monitors() and is_busy().
// Ensure the object-monitor relationship remains stable while there's contention.
Atomic::inc_ptr(&_count);
Atomic::inc(&_count);
EventJavaMonitorEnter event;
@ -384,7 +381,7 @@ void NOINLINE ObjectMonitor::enter(TRAPS) {
// acquire it.
}
Atomic::dec_ptr(&_count);
Atomic::dec(&_count);
assert(_count >= 0, "invariant");
Self->_Stalled = 0;
@ -440,7 +437,6 @@ int ObjectMonitor::TryLock(Thread * Self) {
// Either guarantee _recursions == 0 or set _recursions = 0.
assert(_recursions == 0, "invariant");
assert(_owner == Self, "invariant");
// CONSIDER: set or assert that OwnerIsThread == 1
return 1;
}
// The lock had been free momentarily, but we lost the race to the lock.
@ -922,7 +918,6 @@ void NOINLINE ObjectMonitor::exit(bool not_suspended, TRAPS) {
assert(_recursions == 0, "invariant");
_owner = THREAD;
_recursions = 0;
OwnerIsThread = 1;
} else {
// Apparent unbalanced locking ...
// Naively we'd like to throw IllegalMonitorStateException.
@ -1346,7 +1341,6 @@ intptr_t ObjectMonitor::complete_exit(TRAPS) {
assert(_recursions == 0, "internal state error");
_owner = THREAD; // Convert from basiclock addr to Thread addr
_recursions = 0;
OwnerIsThread = 1;
}
}
@ -1385,7 +1379,6 @@ void ObjectMonitor::reenter(intptr_t recursions, TRAPS) {
if (THREAD->is_lock_owned((address) _owner)) { \
_owner = THREAD; /* Convert from basiclock addr to Thread addr */ \
_recursions = 0; \
OwnerIsThread = 1; \
} else { \
TEVENT(Throw IMSX); \
THROW(vmSymbols::java_lang_IllegalMonitorStateException()); \
@ -1906,8 +1899,8 @@ void ObjectMonitor::notifyAll(TRAPS) {
// a contending thread could enqueue itself on the cxq and then spin locally
// on a thread-specific variable such as its ParkEvent._Event flag.
// That's left as an exercise for the reader. Note that global spinning is
// not problematic on Niagara, as the L2$ serves the interconnect and has both
// low latency and massive bandwidth.
// not problematic on Niagara, as the L2 cache serves the interconnect and
// has both low latency and massive bandwidth.
//
// Broadly, we can fix the spin frequency -- that is, the % of contended lock
// acquisition attempts where we opt to spin -- at 100% and vary the spin count
@ -2208,7 +2201,7 @@ int ObjectMonitor::TrySpin_VaryDuration(Thread * Self) {
// as advisory.
//
// Beware too, that _owner is sometimes a BasicLock address and sometimes
// a thread pointer. We differentiate the two cases with OwnerIsThread.
// a thread pointer.
// Alternately, we might tag the type (thread pointer vs basiclock pointer)
// with the LSB of _owner. Another option would be to probablistically probe
// the putative _owner->TypeTag value.
@ -2230,9 +2223,7 @@ int ObjectMonitor::TrySpin_VaryDuration(Thread * Self) {
int ObjectMonitor::NotRunnable(Thread * Self, Thread * ox) {
// Check either OwnerIsThread or ox->TypeTag == 2BAD.
if (!OwnerIsThread) return 0;
// Check ox->TypeTag == 2BAD.
if (ox == NULL) return 0;
// Avoid transitive spinning ...
@ -2399,20 +2390,6 @@ void ObjectMonitor::Initialize() {
}
}
// Compile-time asserts
// When possible, it's better to catch errors deterministically at
// compile-time than at runtime. The down-side to using compile-time
// asserts is that error message -- often something about negative array
// indices -- is opaque.
#define CTASSERT(x) { int tag[1-(2*!(x))]; printf ("Tag @" INTPTR_FORMAT "\n", (intptr_t)tag); }
void ObjectMonitor::ctAsserts() {
CTASSERT(offset_of (ObjectMonitor, _header) == 0);
}
static char * kvGet(char * kvList, const char * Key) {
if (kvList == NULL) return NULL;
size_t n = strlen(Key);
@ -2526,6 +2503,8 @@ void ObjectMonitor::sanity_checks() {
if (verbose) {
tty->print_cr("INFO: sizeof(ObjectMonitor)=" SIZE_FORMAT,
sizeof(ObjectMonitor));
tty->print_cr("INFO: sizeof(PaddedEnd<ObjectMonitor>)=" SIZE_FORMAT,
sizeof(PaddedEnd<ObjectMonitor>));
}
uint cache_line_size = VM_Version::L1_data_cache_line_size();
@ -2559,9 +2538,9 @@ void ObjectMonitor::sanity_checks() {
warning_cnt++;
}
if ((sizeof(ObjectMonitor) % cache_line_size) != 0) {
tty->print_cr("WARNING: ObjectMonitor size is not a multiple of "
"a cache line which permits false sharing.");
if ((sizeof(PaddedEnd<ObjectMonitor>) % cache_line_size) != 0) {
tty->print_cr("WARNING: PaddedEnd<ObjectMonitor> size is not a "
"multiple of a cache line which permits false sharing.");
warning_cnt++;
}
}