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8343205: CompileBroker::possibly_add_compiler_threads excessively polls available memory

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Reviewed-by: thartmann, kvn
This commit is contained in:
Martin Doerr 2024-11-04 09:58:51 +00:00
parent df08a9ec0d
commit 75801992a7
2 changed files with 27 additions and 11 deletions
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36
src/hotspot/share/compiler/compileBroker.cpp
View File

@ -1023,18 +1023,34 @@ void CompileBroker::init_compiler_threads() {
void CompileBroker::possibly_add_compiler_threads(JavaThread* THREAD) {
int old_c2_count = 0, new_c2_count = 0, old_c1_count = 0, new_c1_count = 0;
const int c2_tasks_per_thread = 2, c1_tasks_per_thread = 4;
// Quick check if we already have enough compiler threads without taking the lock.
// Numbers may change concurrently, so we read them again after we have the lock.
if (_c2_compile_queue != nullptr) {
old_c2_count = get_c2_thread_count();
new_c2_count = MIN2(_c2_count, _c2_compile_queue->size() / c2_tasks_per_thread);
}
if (_c1_compile_queue != nullptr) {
old_c1_count = get_c1_thread_count();
new_c1_count = MIN2(_c1_count, _c1_compile_queue->size() / c1_tasks_per_thread);
}
if (new_c2_count <= old_c2_count && new_c1_count <= old_c1_count) return;
// Now, we do the more expensive operations.
julong free_memory = os::free_memory();
// If SegmentedCodeCache is off, both values refer to the single heap (with type CodeBlobType::All).
size_t available_cc_np = CodeCache::unallocated_capacity(CodeBlobType::MethodNonProfiled),
available_cc_p = CodeCache::unallocated_capacity(CodeBlobType::MethodProfiled);
size_t available_cc_np = CodeCache::unallocated_capacity(CodeBlobType::MethodNonProfiled),
available_cc_p = CodeCache::unallocated_capacity(CodeBlobType::MethodProfiled);
// Only do attempt to start additional threads if the lock is free.
// Only attempt to start additional threads if the lock is free.
if (!CompileThread_lock->try_lock()) return;
if (_c2_compile_queue != nullptr) {
int old_c2_count = _compilers[1]->num_compiler_threads();
int new_c2_count = MIN4(_c2_count,
_c2_compile_queue->size() / 2,
old_c2_count = get_c2_thread_count();
new_c2_count = MIN4(_c2_count,
_c2_compile_queue->size() / c2_tasks_per_thread,
(int)(free_memory / (200*M)),
(int)(available_cc_np / (128*K)));
@ -1070,7 +1086,7 @@ void CompileBroker::possibly_add_compiler_threads(JavaThread* THREAD) {
break;
}
// Check if another thread has beaten us during the Java calls.
if (_compilers[1]->num_compiler_threads() != i) break;
if (get_c2_thread_count() != i) break;
jobject thread_handle = JNIHandles::make_global(thread_oop);
assert(compiler2_object(i) == nullptr, "Old one must be released!");
_compiler2_objects[i] = thread_handle;
@ -1093,9 +1109,9 @@ void CompileBroker::possibly_add_compiler_threads(JavaThread* THREAD) {
}
if (_c1_compile_queue != nullptr) {
int old_c1_count = _compilers[0]->num_compiler_threads();
int new_c1_count = MIN4(_c1_count,
_c1_compile_queue->size() / 4,
old_c1_count = get_c1_thread_count();
new_c1_count = MIN4(_c1_count,
_c1_compile_queue->size() / c1_tasks_per_thread,
(int)(free_memory / (100*M)),
(int)(available_cc_p / (128*K)));

2
src/hotspot/share/compiler/compileBroker.hpp
View File

@ -87,7 +87,7 @@ class CompileQueue : public CHeapObj<mtCompiler> {
CompileTask* _first_stale;
int _size;
volatile int _size;
int _peak_size;
uint _total_added;
uint _total_removed;