Mercurial > hg > truffle
diff src/share/vm/gc_implementation/g1/concurrentG1RefineThread.cpp @ 1111:44f61c24ddab
6862387: tune concurrent refinement further
Summary: Reworked the concurrent refinement: threads activation, feedback-based threshold adjustment, other miscellaneous fixes.
Reviewed-by: apetrusenko, tonyp
author | iveresov |
---|---|
date | Wed, 16 Dec 2009 15:12:51 -0800 |
parents | 035d2e036a9b |
children | b81f3572f355 |
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--- a/src/share/vm/gc_implementation/g1/concurrentG1RefineThread.cpp Fri Dec 11 09:30:48 2009 -0800 +++ b/src/share/vm/gc_implementation/g1/concurrentG1RefineThread.cpp Wed Dec 16 15:12:51 2009 -0800 @@ -25,10 +25,6 @@ #include "incls/_precompiled.incl" #include "incls/_concurrentG1RefineThread.cpp.incl" -// ======= Concurrent Mark Thread ======== - -// The CM thread is created when the G1 garbage collector is used - ConcurrentG1RefineThread:: ConcurrentG1RefineThread(ConcurrentG1Refine* cg1r, ConcurrentG1RefineThread *next, int worker_id_offset, int worker_id) : @@ -37,19 +33,42 @@ _worker_id(worker_id), _active(false), _next(next), + _monitor(NULL), _cg1r(cg1r), - _vtime_accum(0.0), - _interval_ms(5.0) + _vtime_accum(0.0) { + + // Each thread has its own monitor. The i-th thread is responsible for signalling + // to thread i+1 if the number of buffers in the queue exceeds a threashold for this + // thread. Monitors are also used to wake up the threads during termination. + // The 0th worker in notified by mutator threads and has a special monitor. + // The last worker is used for young gen rset size sampling. + if (worker_id > 0) { + _monitor = new Monitor(Mutex::nonleaf, "Refinement monitor", true); + } else { + _monitor = DirtyCardQ_CBL_mon; + } + initialize(); create_and_start(); } +void ConcurrentG1RefineThread::initialize() { + if (_worker_id < cg1r()->worker_thread_num()) { + // Current thread activation threshold + _threshold = MIN2<int>(cg1r()->thread_threshold_step() * (_worker_id + 1) + cg1r()->green_zone(), + cg1r()->yellow_zone()); + // A thread deactivates once the number of buffer reached a deactivation threshold + _deactivation_threshold = MAX2<int>(_threshold - cg1r()->thread_threshold_step(), cg1r()->green_zone()); + } else { + set_active(true); + } +} + void ConcurrentG1RefineThread::sample_young_list_rs_lengths() { G1CollectedHeap* g1h = G1CollectedHeap::heap(); G1CollectorPolicy* g1p = g1h->g1_policy(); if (g1p->adaptive_young_list_length()) { int regions_visited = 0; - g1h->young_list_rs_length_sampling_init(); while (g1h->young_list_rs_length_sampling_more()) { g1h->young_list_rs_length_sampling_next(); @@ -70,99 +89,121 @@ } } -void ConcurrentG1RefineThread::run() { - initialize_in_thread(); +void ConcurrentG1RefineThread::run_young_rs_sampling() { + DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); _vtime_start = os::elapsedVTime(); - wait_for_universe_init(); + while(!_should_terminate) { + _sts.join(); + sample_young_list_rs_lengths(); + _sts.leave(); - while (!_should_terminate) { - DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); - // Wait for completed log buffers to exist. - { - MutexLockerEx x(DirtyCardQ_CBL_mon, Mutex::_no_safepoint_check_flag); - while (((_worker_id == 0 && !dcqs.process_completed_buffers()) || - (_worker_id > 0 && !is_active())) && - !_should_terminate) { - DirtyCardQ_CBL_mon->wait(Mutex::_no_safepoint_check_flag); - } - } - - if (_should_terminate) { - return; + if (os::supports_vtime()) { + _vtime_accum = (os::elapsedVTime() - _vtime_start); + } else { + _vtime_accum = 0.0; } - // Now we take them off (this doesn't hold locks while it applies - // closures.) (If we did a full collection, then we'll do a full - // traversal. - _sts.join(); - int n_logs = 0; - int lower_limit = 0; - double start_vtime_sec; // only used when G1SmoothConcRefine is on - int prev_buffer_num; // only used when G1SmoothConcRefine is on - // This thread activation threshold - int threshold = G1UpdateBufferQueueProcessingThreshold * _worker_id; - // Next thread activation threshold - int next_threshold = threshold + G1UpdateBufferQueueProcessingThreshold; - int deactivation_threshold = MAX2<int>(threshold - G1UpdateBufferQueueProcessingThreshold / 2, 0); + MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag); + if (_should_terminate) { + break; + } + _monitor->wait(Mutex::_no_safepoint_check_flag, G1ConcRefineServiceInterval); + } +} - if (G1SmoothConcRefine) { - lower_limit = 0; - start_vtime_sec = os::elapsedVTime(); - prev_buffer_num = (int) dcqs.completed_buffers_num(); - } else { - lower_limit = G1UpdateBufferQueueProcessingThreshold / 4; // For now. +void ConcurrentG1RefineThread::wait_for_completed_buffers() { + DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); + MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag); + while (!_should_terminate && !is_active()) { + _monitor->wait(Mutex::_no_safepoint_check_flag); + } +} + +bool ConcurrentG1RefineThread::is_active() { + DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); + return _worker_id > 0 ? _active : dcqs.process_completed_buffers(); +} + +void ConcurrentG1RefineThread::activate() { + MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag); + if (_worker_id > 0) { + if (G1TraceConcurrentRefinement) { + DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); + gclog_or_tty->print_cr("G1-Refine-activated worker %d, on threshold %d, current %d", + _worker_id, _threshold, (int)dcqs.completed_buffers_num()); } - while (dcqs.apply_closure_to_completed_buffer(_worker_id + _worker_id_offset, lower_limit)) { - double end_vtime_sec; - double elapsed_vtime_sec; - int elapsed_vtime_ms; - int curr_buffer_num = (int) dcqs.completed_buffers_num(); + set_active(true); + } else { + DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); + dcqs.set_process_completed(true); + } + _monitor->notify(); +} - if (G1SmoothConcRefine) { - end_vtime_sec = os::elapsedVTime(); - elapsed_vtime_sec = end_vtime_sec - start_vtime_sec; - elapsed_vtime_ms = (int) (elapsed_vtime_sec * 1000.0); +void ConcurrentG1RefineThread::deactivate() { + MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag); + if (_worker_id > 0) { + if (G1TraceConcurrentRefinement) { + DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); + gclog_or_tty->print_cr("G1-Refine-deactivated worker %d, off threshold %d, current %d", + _worker_id, _deactivation_threshold, (int)dcqs.completed_buffers_num()); + } + set_active(false); + } else { + DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); + dcqs.set_process_completed(false); + } +} + +void ConcurrentG1RefineThread::run() { + initialize_in_thread(); + wait_for_universe_init(); - if (curr_buffer_num > prev_buffer_num || - curr_buffer_num > next_threshold) { - decreaseInterval(elapsed_vtime_ms); - } else if (curr_buffer_num < prev_buffer_num) { - increaseInterval(elapsed_vtime_ms); - } + if (_worker_id >= cg1r()->worker_thread_num()) { + run_young_rs_sampling(); + terminate(); + } + + _vtime_start = os::elapsedVTime(); + while (!_should_terminate) { + DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set(); + + // Wait for work + wait_for_completed_buffers(); + + if (_should_terminate) { + break; + } + + _sts.join(); + + do { + int curr_buffer_num = (int)dcqs.completed_buffers_num(); + // If the number of the buffers falls down into the yellow zone, + // that means that the transition period after the evacuation pause has ended. + if (dcqs.completed_queue_padding() > 0 && curr_buffer_num <= cg1r()->yellow_zone()) { + dcqs.set_completed_queue_padding(0); } - if (_worker_id == 0) { - sample_young_list_rs_lengths(); - } else if (curr_buffer_num < deactivation_threshold) { + + if (_worker_id > 0 && curr_buffer_num <= _deactivation_threshold) { // If the number of the buffer has fallen below our threshold // we should deactivate. The predecessor will reactivate this // thread should the number of the buffers cross the threshold again. - MutexLockerEx x(DirtyCardQ_CBL_mon, Mutex::_no_safepoint_check_flag); deactivate(); - if (G1TraceConcurrentRefinement) { - gclog_or_tty->print_cr("G1-Refine-deactivated worker %d", _worker_id); - } break; } // Check if we need to activate the next thread. - if (curr_buffer_num > next_threshold && _next != NULL && !_next->is_active()) { - MutexLockerEx x(DirtyCardQ_CBL_mon, Mutex::_no_safepoint_check_flag); + if (_next != NULL && !_next->is_active() && curr_buffer_num > _next->_threshold) { _next->activate(); - DirtyCardQ_CBL_mon->notify_all(); - if (G1TraceConcurrentRefinement) { - gclog_or_tty->print_cr("G1-Refine-activated worker %d", _next->_worker_id); - } } + } while (dcqs.apply_closure_to_completed_buffer(_worker_id + _worker_id_offset, cg1r()->green_zone())); - if (G1SmoothConcRefine) { - prev_buffer_num = curr_buffer_num; - _sts.leave(); - os::sleep(Thread::current(), (jlong) _interval_ms, false); - _sts.join(); - start_vtime_sec = os::elapsedVTime(); - } - n_logs++; + // We can exit the loop above while being active if there was a yield request. + if (is_active()) { + deactivate(); } + _sts.leave(); if (os::supports_vtime()) { @@ -172,7 +213,6 @@ } } assert(_should_terminate, "just checking"); - terminate(); } @@ -191,8 +231,8 @@ } { - MutexLockerEx x(DirtyCardQ_CBL_mon, Mutex::_no_safepoint_check_flag); - DirtyCardQ_CBL_mon->notify_all(); + MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag); + _monitor->notify(); } {