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8203394: Implementation of JEP 331: Low-Overhead Heap Profiling

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Implement Low-Overhead Heap Profiling

Reviewed-by: eosterlund, gthornbr, rehn, sspitsyn, tschatzl
This commit is contained in:
Jean Christophe Beyler 2018-06-15 00:49:54 -07:00
parent 724e41cbb6
commit 6129ed590c
17 changed files with 569 additions and 76 deletions
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51
src/hotspot/share/gc/shared/threadLocalAllocBuffer.cpp
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@ -45,6 +45,14 @@ void ThreadLocalAllocBuffer::clear_before_allocation() {
make_parsable(true); // also retire the TLAB
}
size_t ThreadLocalAllocBuffer::remaining() {
if (end() == NULL) {
return 0;
}
return pointer_delta(hard_end(), top());
}
void ThreadLocalAllocBuffer::accumulate_statistics_before_gc() {
global_stats()->initialize();
@ -121,10 +129,12 @@ void ThreadLocalAllocBuffer::make_parsable(bool retire, bool zap) {
set_top(NULL);
set_pf_top(NULL);
set_end(NULL);
set_allocation_end(NULL);
}
}
assert(!(retire || ZeroTLAB) ||
(start() == NULL && end() == NULL && top() == NULL),
(start() == NULL && end() == NULL && top() == NULL &&
_allocation_end == NULL),
"TLAB must be reset");
}
@ -172,8 +182,13 @@ void ThreadLocalAllocBuffer::fill(HeapWord* start,
_allocated_size += new_size;
print_stats("fill");
assert(top <= start + new_size - alignment_reserve(), "size too small");
initialize(start, top, start + new_size - alignment_reserve());
if (ThreadHeapSampler::enabled()) {
set_sample_end();
}
// Reset amount of internal fragmentation
set_refill_waste_limit(initial_refill_waste_limit());
}
@ -185,6 +200,7 @@ void ThreadLocalAllocBuffer::initialize(HeapWord* start,
set_top(top);
set_pf_top(top);
set_end(end);
set_allocation_end(end);
invariants();
}
@ -306,12 +322,45 @@ void ThreadLocalAllocBuffer::verify() {
guarantee(p == top(), "end of last object must match end of space");
}
void ThreadLocalAllocBuffer::set_sample_end() {
size_t heap_words_remaining = pointer_delta(_end, _top);
size_t bytes_until_sample = myThread()->heap_sampler().bytes_until_sample();
size_t words_until_sample = bytes_until_sample / HeapWordSize;;
if (heap_words_remaining > words_until_sample) {
HeapWord* new_end = _top + words_until_sample;
set_end(new_end);
_bytes_since_last_sample_point = bytes_until_sample;
} else {
_bytes_since_last_sample_point = heap_words_remaining * HeapWordSize;;
}
}
Thread* ThreadLocalAllocBuffer::myThread() {
return (Thread*)(((char *)this) +
in_bytes(start_offset()) -
in_bytes(Thread::tlab_start_offset()));
}
void ThreadLocalAllocBuffer::set_back_allocation_end() {
_end = _allocation_end;
}
HeapWord* ThreadLocalAllocBuffer::allocate_sampled_object(size_t size) {
set_back_allocation_end();
HeapWord* result = allocate(size);
if (result) {
myThread()->heap_sampler().check_for_sampling(result, size * HeapWordSize, _bytes_since_last_sample_point);
set_sample_end();
}
return result;
}
HeapWord* ThreadLocalAllocBuffer::hard_end() {
return _allocation_end + alignment_reserve();
}
GlobalTLABStats::GlobalTLABStats() :
_allocating_threads_avg(TLABAllocationWeight) {