1.1 --- a/src/share/vm/gc_implementation/g1/g1RemSet.cpp Tue Feb 09 13:56:09 2010 -0800
1.2 +++ b/src/share/vm/gc_implementation/g1/g1RemSet.cpp Thu Feb 11 15:52:19 2010 -0800
1.3 @@ -155,8 +155,8 @@
1.4 G1BlockOffsetSharedArray* _bot_shared;
1.5 CardTableModRefBS *_ct_bs;
1.6 int _worker_i;
1.7 + int _block_size;
1.8 bool _try_claimed;
1.9 - size_t _min_skip_distance, _max_skip_distance;
1.10 public:
1.11 ScanRSClosure(OopsInHeapRegionClosure* oc, int worker_i) :
1.12 _oc(oc),
1.13 @@ -168,8 +168,7 @@
1.14 _g1h = G1CollectedHeap::heap();
1.15 _bot_shared = _g1h->bot_shared();
1.16 _ct_bs = (CardTableModRefBS*) (_g1h->barrier_set());
1.17 - _min_skip_distance = 16;
1.18 - _max_skip_distance = 2 * _g1h->n_par_threads() * _min_skip_distance;
1.19 + _block_size = MAX2<int>(G1RSetScanBlockSize, 1);
1.20 }
1.21
1.22 void set_try_claimed() { _try_claimed = true; }
1.23 @@ -225,12 +224,15 @@
1.24 HeapRegionRemSetIterator* iter = _g1h->rem_set_iterator(_worker_i);
1.25 hrrs->init_iterator(iter);
1.26 size_t card_index;
1.27 - size_t skip_distance = 0, current_card = 0, jump_to_card = 0;
1.28 - while (iter->has_next(card_index)) {
1.29 - if (current_card < jump_to_card) {
1.30 - ++current_card;
1.31 - continue;
1.32 +
1.33 + // We claim cards in block so as to recude the contention. The block size is determined by
1.34 + // the G1RSetScanBlockSize parameter.
1.35 + size_t jump_to_card = hrrs->iter_claimed_next(_block_size);
1.36 + for (size_t current_card = 0; iter->has_next(card_index); current_card++) {
1.37 + if (current_card >= jump_to_card + _block_size) {
1.38 + jump_to_card = hrrs->iter_claimed_next(_block_size);
1.39 }
1.40 + if (current_card < jump_to_card) continue;
1.41 HeapWord* card_start = _g1h->bot_shared()->address_for_index(card_index);
1.42 #if 0
1.43 gclog_or_tty->print("Rem set iteration yielded card [" PTR_FORMAT ", " PTR_FORMAT ").\n",
1.44 @@ -247,22 +249,14 @@
1.45
1.46 // If the card is dirty, then we will scan it during updateRS.
1.47 if (!card_region->in_collection_set() && !_ct_bs->is_card_dirty(card_index)) {
1.48 - if (!_ct_bs->is_card_claimed(card_index) && _ct_bs->claim_card(card_index)) {
1.49 - scanCard(card_index, card_region);
1.50 - } else if (_try_claimed) {
1.51 - if (jump_to_card == 0 || jump_to_card != current_card) {
1.52 - // We did some useful work in the previous iteration.
1.53 - // Decrease the distance.
1.54 - skip_distance = MAX2(skip_distance >> 1, _min_skip_distance);
1.55 - } else {
1.56 - // Previous iteration resulted in a claim failure.
1.57 - // Increase the distance.
1.58 - skip_distance = MIN2(skip_distance << 1, _max_skip_distance);
1.59 - }
1.60 - jump_to_card = current_card + skip_distance;
1.61 - }
1.62 + // We make the card as "claimed" lazily (so races are possible but they're benign),
1.63 + // which reduces the number of duplicate scans (the rsets of the regions in the cset
1.64 + // can intersect).
1.65 + if (!_ct_bs->is_card_claimed(card_index)) {
1.66 + _ct_bs->set_card_claimed(card_index);
1.67 + scanCard(card_index, card_region);
1.68 + }
1.69 }
1.70 - ++current_card;
1.71 }
1.72 if (!_try_claimed) {
1.73 hrrs->set_iter_complete();
1.74 @@ -299,30 +293,18 @@
1.75 double rs_time_start = os::elapsedTime();
1.76 HeapRegion *startRegion = calculateStartRegion(worker_i);
1.77
1.78 - BufferingOopsInHeapRegionClosure boc(oc);
1.79 - ScanRSClosure scanRScl(&boc, worker_i);
1.80 + ScanRSClosure scanRScl(oc, worker_i);
1.81 _g1->collection_set_iterate_from(startRegion, &scanRScl);
1.82 scanRScl.set_try_claimed();
1.83 _g1->collection_set_iterate_from(startRegion, &scanRScl);
1.84
1.85 - boc.done();
1.86 - double closure_app_time_sec = boc.closure_app_seconds();
1.87 - double scan_rs_time_sec = (os::elapsedTime() - rs_time_start) -
1.88 - closure_app_time_sec;
1.89 - double closure_app_time_ms = closure_app_time_sec * 1000.0;
1.90 + double scan_rs_time_sec = os::elapsedTime() - rs_time_start;
1.91
1.92 assert( _cards_scanned != NULL, "invariant" );
1.93 _cards_scanned[worker_i] = scanRScl.cards_done();
1.94
1.95 _g1p->record_scan_rs_start_time(worker_i, rs_time_start * 1000.0);
1.96 _g1p->record_scan_rs_time(worker_i, scan_rs_time_sec * 1000.0);
1.97 -
1.98 - double scan_new_refs_time_ms = _g1p->get_scan_new_refs_time(worker_i);
1.99 - if (scan_new_refs_time_ms > 0.0) {
1.100 - closure_app_time_ms += scan_new_refs_time_ms;
1.101 - }
1.102 -
1.103 - _g1p->record_obj_copy_time(worker_i, closure_app_time_ms);
1.104 }
1.105
1.106 void HRInto_G1RemSet::updateRS(int worker_i) {
1.107 @@ -449,9 +431,8 @@
1.108 oc->do_oop(p);
1.109 }
1.110 }
1.111 - _g1p->record_scan_new_refs_time(worker_i,
1.112 - (os::elapsedTime() - scan_new_refs_start_sec)
1.113 - * 1000.0);
1.114 + double scan_new_refs_time_ms = (os::elapsedTime() - scan_new_refs_start_sec) * 1000.0;
1.115 + _g1p->record_scan_new_refs_time(worker_i, scan_new_refs_time_ms);
1.116 }
1.117
1.118 void HRInto_G1RemSet::cleanupHRRS() {
