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8032463: VirtualDispatch test timeout with DeoptimizeALot

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Introduce code aging for warm method detection

Reviewed-by: kvn, twisti
This commit is contained in:
Igor Veresov 2014-05-13 11:32:10 -07:00
parent 5938d3d5b9
commit 54db2c2d61
27 changed files with 283 additions and 69 deletions
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114
hotspot/src/share/vm/runtime/sweeper.cpp
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@ -573,37 +573,7 @@ int NMethodSweeper::process_nmethod(nmethod *nm) {
SWEEP(nm);
}
} else {
if (UseCodeCacheFlushing) {
if (!nm->is_locked_by_vm() && !nm->is_osr_method() && !nm->is_native_method()) {
// Do not make native methods and OSR-methods not-entrant
nm->dec_hotness_counter();
// Get the initial value of the hotness counter. This value depends on the
// ReservedCodeCacheSize
int reset_val = hotness_counter_reset_val();
int time_since_reset = reset_val - nm->hotness_counter();
double threshold = -reset_val + (CodeCache::reverse_free_ratio() * NmethodSweepActivity);
// The less free space in the code cache we have - the bigger reverse_free_ratio() is.
// I.e., 'threshold' increases with lower available space in the code cache and a higher
// NmethodSweepActivity. If the current hotness counter - which decreases from its initial
// value until it is reset by stack walking - is smaller than the computed threshold, the
// corresponding nmethod is considered for removal.
if ((NmethodSweepActivity > 0) && (nm->hotness_counter() < threshold) && (time_since_reset > 10)) {
// A method is marked as not-entrant if the method is
// 1) 'old enough': nm->hotness_counter() < threshold
// 2) The method was in_use for a minimum amount of time: (time_since_reset > 10)
// The second condition is necessary if we are dealing with very small code cache
// sizes (e.g., <10m) and the code cache size is too small to hold all hot methods.
// The second condition ensures that methods are not immediately made not-entrant
// after compilation.
nm->make_not_entrant();
// Code cache state change is tracked in make_not_entrant()
if (PrintMethodFlushing && Verbose) {
tty->print_cr("### Nmethod %d/" PTR_FORMAT "made not-entrant: hotness counter %d/%d threshold %f",
nm->compile_id(), nm, nm->hotness_counter(), reset_val, threshold);
}
}
}
}
possibly_flush(nm);
// Clean-up all inline caches that point to zombie/non-reentrant methods
MutexLocker cl(CompiledIC_lock);
nm->cleanup_inline_caches();
@ -612,6 +582,88 @@ int NMethodSweeper::process_nmethod(nmethod *nm) {
return freed_memory;
}
void NMethodSweeper::possibly_flush(nmethod* nm) {
if (UseCodeCacheFlushing) {
if (!nm->is_locked_by_vm() && !nm->is_osr_method() && !nm->is_native_method()) {
bool make_not_entrant = false;
// Do not make native methods and OSR-methods not-entrant
nm->dec_hotness_counter();
// Get the initial value of the hotness counter. This value depends on the
// ReservedCodeCacheSize
int reset_val = hotness_counter_reset_val();
int time_since_reset = reset_val - nm->hotness_counter();
double threshold = -reset_val + (CodeCache::reverse_free_ratio() * NmethodSweepActivity);
// The less free space in the code cache we have - the bigger reverse_free_ratio() is.
// I.e., 'threshold' increases with lower available space in the code cache and a higher
// NmethodSweepActivity. If the current hotness counter - which decreases from its initial
// value until it is reset by stack walking - is smaller than the computed threshold, the
// corresponding nmethod is considered for removal.
if ((NmethodSweepActivity > 0) && (nm->hotness_counter() < threshold) && (time_since_reset > MinPassesBeforeFlush)) {
// A method is marked as not-entrant if the method is
// 1) 'old enough': nm->hotness_counter() < threshold
// 2) The method was in_use for a minimum amount of time: (time_since_reset > MinPassesBeforeFlush)
// The second condition is necessary if we are dealing with very small code cache
// sizes (e.g., <10m) and the code cache size is too small to hold all hot methods.
// The second condition ensures that methods are not immediately made not-entrant
// after compilation.
make_not_entrant = true;
}
// The stack-scanning low-cost detection may not see the method was used (which can happen for
// flat profiles). Check the age counter for possible data.
if (UseCodeAging && make_not_entrant && (nm->is_compiled_by_c2() || nm->is_compiled_by_c1())) {
MethodCounters* mc = nm->method()->method_counters();
if (mc != NULL) {
// Snapshot the value as it's changed concurrently
int age = mc->nmethod_age();
if (MethodCounters::is_nmethod_hot(age)) {
// The method has gone through flushing, and it became relatively hot that it deopted
// before we could take a look at it. Give it more time to appear in the stack traces,
// proportional to the number of deopts.
MethodData* md = nm->method()->method_data();
if (md != NULL && time_since_reset > (int)(MinPassesBeforeFlush * (md->tenure_traps() + 1))) {
// It's been long enough, we still haven't seen it on stack.
// Try to flush it, but enable counters the next time.
mc->reset_nmethod_age();
} else {
make_not_entrant = false;
}
} else if (MethodCounters::is_nmethod_warm(age)) {
// Method has counters enabled, and the method was used within
// previous MinPassesBeforeFlush sweeps. Reset the counter. Stay in the existing
// compiled state.
mc->reset_nmethod_age();
// delay the next check
nm->set_hotness_counter(NMethodSweeper::hotness_counter_reset_val());
make_not_entrant = false;
} else if (MethodCounters::is_nmethod_age_unset(age)) {
// No counters were used before. Set the counters to the detection
// limit value. If the method is going to be used again it will be compiled
// with counters that we're going to use for analysis the the next time.
mc->reset_nmethod_age();
} else {
// Method was totally idle for 10 sweeps
// The counter already has the initial value, flush it and may be recompile
// later with counters
}
}
}
if (make_not_entrant) {
nm->make_not_entrant();
// Code cache state change is tracked in make_not_entrant()
if (PrintMethodFlushing && Verbose) {
tty->print_cr("### Nmethod %d/" PTR_FORMAT "made not-entrant: hotness counter %d/%d threshold %f",
nm->compile_id(), nm, nm->hotness_counter(), reset_val, threshold);
}
}
}
}
}
// Print out some state information about the current sweep and the
// state of the code cache if it's requested.
void NMethodSweeper::log_sweep(const char* msg, const char* format, ...) {