8139277: Remove ScavengeWithObjectsInToSpace, ParallelOldGCSplitALot, ParallelOldGCSplitInterval, PSAdjustTenuredGenForMinorPause and PSAdjustYoungGenForMajorPause
Reviewed-by: tschatzl, sjohanss
diff --git a/hotspot/src/share/vm/gc/parallel/psAdaptiveSizePolicy.cpp b/hotspot/src/share/vm/gc/parallel/psAdaptiveSizePolicy.cpp
index d2c7b2b..69720fb 100644
--- a/hotspot/src/share/vm/gc/parallel/psAdaptiveSizePolicy.cpp
+++ b/hotspot/src/share/vm/gc/parallel/psAdaptiveSizePolicy.cpp
@@ -529,10 +529,7 @@
set_decide_at_full_gc(decide_at_full_gc_true);
adjust_promo_for_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
}
- } else if (_avg_minor_pause->padded_average() > gc_minor_pause_goal_sec()) {
- // Adjust only for the minor pause time goal
- adjust_promo_for_minor_pause_time(is_full_gc, &desired_promo_size, &desired_eden_size);
- } else if(adjusted_mutator_cost() < _throughput_goal) {
+ } else if (adjusted_mutator_cost() < _throughput_goal) {
// This branch used to require that (mutator_cost() > 0.0 in 1.4.2.
// This sometimes resulted in skipping to the minimize footprint
// code. Change this to try and reduce GC time if mutator time is
@@ -670,36 +667,6 @@
}
}
-void PSAdaptiveSizePolicy::adjust_promo_for_minor_pause_time(bool is_full_gc,
- size_t* desired_promo_size_ptr, size_t* desired_eden_size_ptr) {
-
- if (PSAdjustTenuredGenForMinorPause) {
- if (is_full_gc) {
- set_decide_at_full_gc(decide_at_full_gc_true);
- }
- // If the desired eden size is as small as it will get,
- // try to adjust the old gen size.
- if (*desired_eden_size_ptr <= _space_alignment) {
- // Vary the old gen size to reduce the young gen pause. This
- // may not be a good idea. This is just a test.
- if (minor_pause_old_estimator()->decrement_will_decrease()) {
- set_change_old_gen_for_min_pauses(decrease_old_gen_for_min_pauses_true);
- *desired_promo_size_ptr =
- _promo_size - promo_decrement_aligned_down(*desired_promo_size_ptr);
- } else {
- set_change_old_gen_for_min_pauses(increase_old_gen_for_min_pauses_true);
- size_t promo_heap_delta =
- promo_increment_with_supplement_aligned_up(*desired_promo_size_ptr);
- if ((*desired_promo_size_ptr + promo_heap_delta) >
- *desired_promo_size_ptr) {
- *desired_promo_size_ptr =
- _promo_size + promo_heap_delta;
- }
- }
- }
- }
-}
-
void PSAdaptiveSizePolicy::adjust_eden_for_minor_pause_time(bool is_full_gc,
size_t* desired_eden_size_ptr) {
@@ -733,10 +700,7 @@
// a change less than the required alignment is probably not worth
// attempting.
- if (_avg_minor_pause->padded_average() > _avg_major_pause->padded_average()) {
- adjust_promo_for_minor_pause_time(is_full_gc, desired_promo_size_ptr, desired_eden_size_ptr);
- // major pause adjustments
- } else if (is_full_gc) {
+ if (_avg_minor_pause->padded_average() <= _avg_major_pause->padded_average() && is_full_gc) {
// Adjust for the major pause time only at full gc's because the
// affects of a change can only be seen at full gc's.
@@ -774,44 +738,8 @@
// a change less than the required alignment is probably not worth
// attempting.
if (_avg_minor_pause->padded_average() > _avg_major_pause->padded_average()) {
- adjust_eden_for_minor_pause_time(is_full_gc,
- desired_eden_size_ptr);
- // major pause adjustments
- } else if (is_full_gc) {
- // Adjust for the major pause time only at full gc's because the
- // affects of a change can only be seen at full gc's.
- if (PSAdjustYoungGenForMajorPause) {
- // If the promo size is at the minimum (i.e., the old gen
- // size will not actually decrease), consider changing the
- // young gen size.
- if (*desired_promo_size_ptr < _space_alignment) {
- // If increasing the young generation will decrease the old gen
- // pause, do it.
- // During startup there is noise in the statistics for deciding
- // on whether to increase or decrease the young gen size. For
- // some number of iterations, just try to increase the young
- // gen size if the major pause is too long to try and establish
- // good statistics for later decisions.
- if (major_pause_young_estimator()->increment_will_decrease() ||
- (_young_gen_change_for_major_pause_count
- <= AdaptiveSizePolicyInitializingSteps)) {
- set_change_young_gen_for_maj_pauses(
- increase_young_gen_for_maj_pauses_true);
- eden_heap_delta = eden_increment_aligned_up(*desired_eden_size_ptr);
- *desired_eden_size_ptr = _eden_size + eden_heap_delta;
- _young_gen_change_for_major_pause_count++;
- } else {
- // Record that decreasing the young gen size would decrease
- // the major pause
- set_change_young_gen_for_maj_pauses(
- decrease_young_gen_for_maj_pauses_true);
- eden_heap_delta = eden_decrement_aligned_down(*desired_eden_size_ptr);
- *desired_eden_size_ptr = _eden_size - eden_heap_delta;
- }
- }
- }
+ adjust_eden_for_minor_pause_time(is_full_gc, desired_eden_size_ptr);
}
-
if (PrintAdaptiveSizePolicy && Verbose) {
gclog_or_tty->print_cr(
"PSAdaptiveSizePolicy::adjust_eden_for_pause_time "
diff --git a/hotspot/src/share/vm/gc/parallel/psAdaptiveSizePolicy.hpp b/hotspot/src/share/vm/gc/parallel/psAdaptiveSizePolicy.hpp
index 696ec88..2d3899c 100644
--- a/hotspot/src/share/vm/gc/parallel/psAdaptiveSizePolicy.hpp
+++ b/hotspot/src/share/vm/gc/parallel/psAdaptiveSizePolicy.hpp
@@ -134,10 +134,6 @@
AdaptivePaddedAverage* avg_major_pause() const { return _avg_major_pause; }
double gc_minor_pause_goal_sec() const { return _gc_minor_pause_goal_sec; }
- // Change the young generation size to achieve a minor GC pause time goal
- void adjust_promo_for_minor_pause_time(bool is_full_gc,
- size_t* desired_promo_size_ptr,
- size_t* desired_eden_size_ptr);
void adjust_eden_for_minor_pause_time(bool is_full_gc,
size_t* desired_eden_size_ptr);
// Change the generation sizes to achieve a GC pause time goal
diff --git a/hotspot/src/share/vm/gc/parallel/psParallelCompact.cpp b/hotspot/src/share/vm/gc/parallel/psParallelCompact.cpp
index fae3628..982b1d4 100644
--- a/hotspot/src/share/vm/gc/parallel/psParallelCompact.cpp
+++ b/hotspot/src/share/vm/gc/parallel/psParallelCompact.cpp
@@ -1349,13 +1349,6 @@
PSParallelCompact::compute_dense_prefix(const SpaceId id,
bool maximum_compaction)
{
- if (ParallelOldGCSplitALot) {
- if (_space_info[id].dense_prefix() != _space_info[id].space()->bottom()) {
- // The value was chosen to provoke splitting a young gen space; use it.
- return _space_info[id].dense_prefix();
- }
- }
-
const size_t region_size = ParallelCompactData::RegionSize;
const ParallelCompactData& sd = summary_data();
@@ -1428,220 +1421,9 @@
}
}
-#if 0
- // Something to consider: if the region with the best ratio is 'close to' the
- // first region w/free space, choose the first region with free space
- // ("first-free"). The first-free region is usually near the start of the
- // heap, which means we are copying most of the heap already, so copy a bit
- // more to get complete compaction.
- if (pointer_delta(best_cp, full_cp, sizeof(RegionData)) < 4) {
- _maximum_compaction_gc_num = total_invocations();
- best_cp = full_cp;
- }
-#endif // #if 0
-
return sd.region_to_addr(best_cp);
}
-#ifndef PRODUCT
-void
-PSParallelCompact::fill_with_live_objects(SpaceId id, HeapWord* const start,
- size_t words)
-{
- if (TraceParallelOldGCSummaryPhase) {
- tty->print_cr("fill_with_live_objects [" PTR_FORMAT " " PTR_FORMAT ") "
- SIZE_FORMAT, p2i(start), p2i(start + words), words);
- }
-
- ObjectStartArray* const start_array = _space_info[id].start_array();
- CollectedHeap::fill_with_objects(start, words);
- for (HeapWord* p = start; p < start + words; p += oop(p)->size()) {
- _mark_bitmap.mark_obj(p, words);
- _summary_data.add_obj(p, words);
- start_array->allocate_block(p);
- }
-}
-
-void
-PSParallelCompact::summarize_new_objects(SpaceId id, HeapWord* start)
-{
- ParallelCompactData& sd = summary_data();
- MutableSpace* space = _space_info[id].space();
-
- // Find the source and destination start addresses.
- HeapWord* const src_addr = sd.region_align_down(start);
- HeapWord* dst_addr;
- if (src_addr < start) {
- dst_addr = sd.addr_to_region_ptr(src_addr)->destination();
- } else if (src_addr > space->bottom()) {
- // The start (the original top() value) is aligned to a region boundary so
- // the associated region does not have a destination. Compute the
- // destination from the previous region.
- RegionData* const cp = sd.addr_to_region_ptr(src_addr) - 1;
- dst_addr = cp->destination() + cp->data_size();
- } else {
- // Filling the entire space.
- dst_addr = space->bottom();
- }
- assert(dst_addr != NULL, "sanity");
-
- // Update the summary data.
- bool result = _summary_data.summarize(_space_info[id].split_info(),
- src_addr, space->top(), NULL,
- dst_addr, space->end(),
- _space_info[id].new_top_addr());
- assert(result, "should not fail: bad filler object size");
-}
-
-void
-PSParallelCompact::provoke_split_fill_survivor(SpaceId id)
-{
- if (total_invocations() % (ParallelOldGCSplitInterval * 3) != 0) {
- return;
- }
-
- MutableSpace* const space = _space_info[id].space();
- if (space->is_empty()) {
- HeapWord* b = space->bottom();
- HeapWord* t = b + space->capacity_in_words() / 2;
- space->set_top(t);
- if (ZapUnusedHeapArea) {
- space->set_top_for_allocations();
- }
-
- size_t min_size = CollectedHeap::min_fill_size();
- size_t obj_len = min_size;
- while (b + obj_len <= t) {
- CollectedHeap::fill_with_object(b, obj_len);
- mark_bitmap()->mark_obj(b, obj_len);
- summary_data().add_obj(b, obj_len);
- b += obj_len;
- obj_len = (obj_len & (min_size*3)) + min_size; // 8 16 24 32 8 16 24 32 ...
- }
- if (b < t) {
- // The loop didn't completely fill to t (top); adjust top downward.
- space->set_top(b);
- if (ZapUnusedHeapArea) {
- space->set_top_for_allocations();
- }
- }
-
- HeapWord** nta = _space_info[id].new_top_addr();
- bool result = summary_data().summarize(_space_info[id].split_info(),
- space->bottom(), space->top(), NULL,
- space->bottom(), space->end(), nta);
- assert(result, "space must fit into itself");
- }
-}
-
-void
-PSParallelCompact::provoke_split(bool & max_compaction)
-{
- if (total_invocations() % ParallelOldGCSplitInterval != 0) {
- return;
- }
-
- const size_t region_size = ParallelCompactData::RegionSize;
- ParallelCompactData& sd = summary_data();
-
- MutableSpace* const eden_space = _space_info[eden_space_id].space();
- MutableSpace* const from_space = _space_info[from_space_id].space();
- const size_t eden_live = pointer_delta(eden_space->top(),
- _space_info[eden_space_id].new_top());
- const size_t from_live = pointer_delta(from_space->top(),
- _space_info[from_space_id].new_top());
-
- const size_t min_fill_size = CollectedHeap::min_fill_size();
- const size_t eden_free = pointer_delta(eden_space->end(), eden_space->top());
- const size_t eden_fillable = eden_free >= min_fill_size ? eden_free : 0;
- const size_t from_free = pointer_delta(from_space->end(), from_space->top());
- const size_t from_fillable = from_free >= min_fill_size ? from_free : 0;
-
- // Choose the space to split; need at least 2 regions live (or fillable).
- SpaceId id;
- MutableSpace* space;
- size_t live_words;
- size_t fill_words;
- if (eden_live + eden_fillable >= region_size * 2) {
- id = eden_space_id;
- space = eden_space;
- live_words = eden_live;
- fill_words = eden_fillable;
- } else if (from_live + from_fillable >= region_size * 2) {
- id = from_space_id;
- space = from_space;
- live_words = from_live;
- fill_words = from_fillable;
- } else {
- return; // Give up.
- }
- assert(fill_words == 0 || fill_words >= min_fill_size, "sanity");
-
- if (live_words < region_size * 2) {
- // Fill from top() to end() w/live objects of mixed sizes.
- HeapWord* const fill_start = space->top();
- live_words += fill_words;
-
- space->set_top(fill_start + fill_words);
- if (ZapUnusedHeapArea) {
- space->set_top_for_allocations();
- }
-
- HeapWord* cur_addr = fill_start;
- while (fill_words > 0) {
- const size_t r = (size_t)os::random() % (region_size / 2) + min_fill_size;
- size_t cur_size = MIN2(align_object_size_(r), fill_words);
- if (fill_words - cur_size < min_fill_size) {
- cur_size = fill_words; // Avoid leaving a fragment too small to fill.
- }
-
- CollectedHeap::fill_with_object(cur_addr, cur_size);
- mark_bitmap()->mark_obj(cur_addr, cur_size);
- sd.add_obj(cur_addr, cur_size);
-
- cur_addr += cur_size;
- fill_words -= cur_size;
- }
-
- summarize_new_objects(id, fill_start);
- }
-
- max_compaction = false;
-
- // Manipulate the old gen so that it has room for about half of the live data
- // in the target young gen space (live_words / 2).
- id = old_space_id;
- space = _space_info[id].space();
- const size_t free_at_end = space->free_in_words();
- const size_t free_target = align_object_size(live_words / 2);
- const size_t dead = pointer_delta(space->top(), _space_info[id].new_top());
-
- if (free_at_end >= free_target + min_fill_size) {
- // Fill space above top() and set the dense prefix so everything survives.
- HeapWord* const fill_start = space->top();
- const size_t fill_size = free_at_end - free_target;
- space->set_top(space->top() + fill_size);
- if (ZapUnusedHeapArea) {
- space->set_top_for_allocations();
- }
- fill_with_live_objects(id, fill_start, fill_size);
- summarize_new_objects(id, fill_start);
- _space_info[id].set_dense_prefix(sd.region_align_down(space->top()));
- } else if (dead + free_at_end > free_target) {
- // Find a dense prefix that makes the right amount of space available.
- HeapWord* cur = sd.region_align_down(space->top());
- HeapWord* cur_destination = sd.addr_to_region_ptr(cur)->destination();
- size_t dead_to_right = pointer_delta(space->end(), cur_destination);
- while (dead_to_right < free_target) {
- cur -= region_size;
- cur_destination = sd.addr_to_region_ptr(cur)->destination();
- dead_to_right = pointer_delta(space->end(), cur_destination);
- }
- _space_info[id].set_dense_prefix(cur);
- }
-}
-#endif // #ifndef PRODUCT
-
void PSParallelCompact::summarize_spaces_quick()
{
for (unsigned int i = 0; i < last_space_id; ++i) {
@@ -1653,12 +1435,6 @@
assert(result, "space must fit into itself");
_space_info[i].set_dense_prefix(space->bottom());
}
-
-#ifndef PRODUCT
- if (ParallelOldGCSplitALot) {
- provoke_split_fill_survivor(to_space_id);
- }
-#endif // #ifndef PRODUCT
}
void PSParallelCompact::fill_dense_prefix_end(SpaceId id)
@@ -1743,8 +1519,7 @@
PSParallelCompact::summarize_space(SpaceId id, bool maximum_compaction)
{
assert(id < last_space_id, "id out of range");
- assert(_space_info[id].dense_prefix() == _space_info[id].space()->bottom() ||
- ParallelOldGCSplitALot && id == old_space_id,
+ assert(_space_info[id].dense_prefix() == _space_info[id].space()->bottom(),
"should have been reset in summarize_spaces_quick()");
const MutableSpace* space = _space_info[id].space();
@@ -1864,11 +1639,6 @@
// XXX - should also try to expand
maximum_compaction = true;
}
-#ifndef PRODUCT
- if (ParallelOldGCSplitALot && old_space_total_live < old_capacity) {
- provoke_split(maximum_compaction);
- }
-#endif // #ifndef PRODUCT
// Old generations.
summarize_space(old_space_id, maximum_compaction);
diff --git a/hotspot/src/share/vm/gc/parallel/psParallelCompact.hpp b/hotspot/src/share/vm/gc/parallel/psParallelCompact.hpp
index 808270a..09f37ef 100644
--- a/hotspot/src/share/vm/gc/parallel/psParallelCompact.hpp
+++ b/hotspot/src/share/vm/gc/parallel/psParallelCompact.hpp
@@ -1059,24 +1059,6 @@
// Clear the summary data source_region field for the specified addresses.
static void clear_source_region(HeapWord* beg_addr, HeapWord* end_addr);
-#ifndef PRODUCT
- // Routines to provoke splitting a young gen space (ParallelOldGCSplitALot).
-
- // Fill the region [start, start + words) with live object(s). Only usable
- // for the old and permanent generations.
- static void fill_with_live_objects(SpaceId id, HeapWord* const start,
- size_t words);
- // Include the new objects in the summary data.
- static void summarize_new_objects(SpaceId id, HeapWord* start);
-
- // Add live objects to a survivor space since it's rare that both survivors
- // are non-empty.
- static void provoke_split_fill_survivor(SpaceId id);
-
- // Add live objects and/or choose the dense prefix to provoke splitting.
- static void provoke_split(bool & maximum_compaction);
-#endif
-
static void summarize_spaces_quick();
static void summarize_space(SpaceId id, bool maximum_compaction);
static void summary_phase(ParCompactionManager* cm, bool maximum_compaction);
diff --git a/hotspot/src/share/vm/gc/parallel/psScavenge.cpp b/hotspot/src/share/vm/gc/parallel/psScavenge.cpp
index 1dd0329..2c5216d6 100644
--- a/hotspot/src/share/vm/gc/parallel/psScavenge.cpp
+++ b/hotspot/src/share/vm/gc/parallel/psScavenge.cpp
@@ -297,11 +297,6 @@
young_gen->eden_space()->accumulate_statistics();
}
- if (ZapUnusedHeapArea) {
- // Save information needed to minimize mangling
- heap->record_gen_tops_before_GC();
- }
-
heap->print_heap_before_gc();
heap->trace_heap_before_gc(&_gc_tracer);
@@ -344,13 +339,10 @@
CardTableExtension::verify_all_young_refs_imprecise();
}
- if (!ScavengeWithObjectsInToSpace) {
- assert(young_gen->to_space()->is_empty(),
- "Attempt to scavenge with live objects in to_space");
- young_gen->to_space()->clear(SpaceDecorator::Mangle);
- } else if (ZapUnusedHeapArea) {
- young_gen->to_space()->mangle_unused_area();
- }
+ assert(young_gen->to_space()->is_empty(),
+ "Attempt to scavenge with live objects in to_space");
+ young_gen->to_space()->clear(SpaceDecorator::Mangle);
+
save_to_space_top_before_gc();
COMPILER2_PRESENT(DerivedPointerTable::clear());
@@ -677,12 +669,6 @@
heap->print_heap_after_gc();
heap->trace_heap_after_gc(&_gc_tracer);
- if (ZapUnusedHeapArea) {
- young_gen->eden_space()->check_mangled_unused_area_complete();
- young_gen->from_space()->check_mangled_unused_area_complete();
- young_gen->to_space()->check_mangled_unused_area_complete();
- }
-
scavenge_exit.update();
if (PrintGCTaskTimeStamps) {
@@ -764,15 +750,13 @@
PSYoungGen* young_gen = heap->young_gen();
PSOldGen* old_gen = heap->old_gen();
- if (!ScavengeWithObjectsInToSpace) {
- // Do not attempt to promote unless to_space is empty
- if (!young_gen->to_space()->is_empty()) {
- _consecutive_skipped_scavenges++;
- if (UsePerfData) {
- counters->update_scavenge_skipped(to_space_not_empty);
- }
- return false;
+ // Do not attempt to promote unless to_space is empty
+ if (!young_gen->to_space()->is_empty()) {
+ _consecutive_skipped_scavenges++;
+ if (UsePerfData) {
+ counters->update_scavenge_skipped(to_space_not_empty);
}
+ return false;
}
// Test to see if the scavenge will likely fail.
diff --git a/hotspot/src/share/vm/runtime/arguments.cpp b/hotspot/src/share/vm/runtime/arguments.cpp
index 4baded2..ca249f2 100644
--- a/hotspot/src/share/vm/runtime/arguments.cpp
+++ b/hotspot/src/share/vm/runtime/arguments.cpp
@@ -2431,20 +2431,6 @@
MarkSweepAlwaysCompactCount = 1; // Move objects every gc.
}
- if (UseParallelOldGC && ParallelOldGCSplitALot) {
- // Settings to encourage splitting.
- if (!FLAG_IS_CMDLINE(NewRatio)) {
- if (FLAG_SET_CMDLINE(uintx, NewRatio, 2) != Flag::SUCCESS) {
- status = false;
- }
- }
- if (!FLAG_IS_CMDLINE(ScavengeBeforeFullGC)) {
- if (FLAG_SET_CMDLINE(bool, ScavengeBeforeFullGC, false) != Flag::SUCCESS) {
- status = false;
- }
- }
- }
-
if (!(UseParallelGC || UseParallelOldGC) && FLAG_IS_DEFAULT(ScavengeBeforeFullGC)) {
FLAG_SET_DEFAULT(ScavengeBeforeFullGC, false);
}
diff --git a/hotspot/src/share/vm/runtime/globals.hpp b/hotspot/src/share/vm/runtime/globals.hpp
index 5d8f4fb..a060b7e 100644
--- a/hotspot/src/share/vm/runtime/globals.hpp
+++ b/hotspot/src/share/vm/runtime/globals.hpp
@@ -1569,14 +1569,6 @@
product(bool, TraceDynamicGCThreads, false, \
"Trace the dynamic GC thread usage") \
\
- develop(bool, ParallelOldGCSplitALot, false, \
- "Provoke splitting (copying data from a young gen space to " \
- "multiple destination spaces)") \
- \
- develop(uintx, ParallelOldGCSplitInterval, 3, \
- "How often to provoke splitting a young gen space") \
- range(0, max_uintx) \
- \
product(uint, ConcGCThreads, 0, \
"Number of threads concurrent gc will use") \
constraint(ConcGCThreadsConstraintFunc,AfterErgo) \
@@ -1595,9 +1587,6 @@
product(bool, ScavengeBeforeFullGC, true, \
"Scavenge youngest generation before each full GC.") \
\
- develop(bool, ScavengeWithObjectsInToSpace, false, \
- "Allow scavenges to occur when to-space contains objects") \
- \
product(bool, UseConcMarkSweepGC, false, \
"Use Concurrent Mark-Sweep GC in the old generation") \
\
@@ -2240,12 +2229,6 @@
"Policy for changing generation size for throughput goals") \
range(0, 1) \
\
- develop(bool, PSAdjustTenuredGenForMinorPause, false, \
- "Adjust tenured generation to achieve a minor pause goal") \
- \
- develop(bool, PSAdjustYoungGenForMajorPause, false, \
- "Adjust young generation to achieve a major pause goal") \
- \
product(uintx, AdaptiveSizePolicyInitializingSteps, 20, \
"Number of steps where heuristics is used before data is used") \
\
