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7113021: G1: automatically enable young gen size auto-tuning when -Xms==-Xmx

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Use a percentage of -Xms as min and another percentage of -Xmx as max for the young gen size

Reviewed-by: tonyp, johnc
This commit is contained in:
Bengt Rutisson 2011-12-21 22:13:31 +01:00
parent 0ebc10bb13
commit 056282a67b
3 changed files with 146 additions and 76 deletions
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130
hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp
View File

@ -136,7 +136,6 @@ G1CollectorPolicy::G1CollectorPolicy() :
_stop_world_start(0.0),
_all_stop_world_times_ms(new NumberSeq()),
_all_yield_times_ms(new NumberSeq()),
_using_new_ratio_calculations(false),
_summary(new Summary()),
@ -409,11 +408,7 @@ G1CollectorPolicy::G1CollectorPolicy() :
initialize_all();
_collectionSetChooser = new CollectionSetChooser();
}
// Increment "i", mod "len"
static void inc_mod(int& i, int len) {
i++; if (i == len) i = 0;
_young_gen_sizer = new G1YoungGenSizer(); // Must be after call to initialize_flags
}
void G1CollectorPolicy::initialize_flags() {
@ -425,39 +420,74 @@ void G1CollectorPolicy::initialize_flags() {
CollectorPolicy::initialize_flags();
}
// The easiest way to deal with the parsing of the NewSize /
// MaxNewSize / etc. parameteres is to re-use the code in the
// TwoGenerationCollectorPolicy class. This is similar to what
// ParallelScavenge does with its GenerationSizer class (see
// ParallelScavengeHeap::initialize()). We might change this in the
// future, but it's a good start.
class G1YoungGenSizer : public TwoGenerationCollectorPolicy {
private:
size_t size_to_region_num(size_t byte_size) {
return MAX2((size_t) 1, byte_size / HeapRegion::GrainBytes);
G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults), _adaptive_size(true) {
assert(G1DefaultMinNewGenPercent <= G1DefaultMaxNewGenPercent, "Min larger than max");
assert(G1DefaultMinNewGenPercent > 0 && G1DefaultMinNewGenPercent < 100, "Min out of bounds");
assert(G1DefaultMaxNewGenPercent > 0 && G1DefaultMaxNewGenPercent < 100, "Max out of bounds");
if (FLAG_IS_CMDLINE(NewRatio)) {
if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio");
} else {
_sizer_kind = SizerNewRatio;
_adaptive_size = false;
return;
}
}
public:
G1YoungGenSizer() {
initialize_flags();
initialize_size_info();
if (FLAG_IS_CMDLINE(NewSize)) {
_min_desired_young_length = MAX2((size_t) 1, NewSize / HeapRegion::GrainBytes);
if (FLAG_IS_CMDLINE(MaxNewSize)) {
_max_desired_young_length = MAX2((size_t) 1, MaxNewSize / HeapRegion::GrainBytes);
_sizer_kind = SizerMaxAndNewSize;
_adaptive_size = _min_desired_young_length == _max_desired_young_length;
} else {
_sizer_kind = SizerNewSizeOnly;
}
} else if (FLAG_IS_CMDLINE(MaxNewSize)) {
_max_desired_young_length = MAX2((size_t) 1, MaxNewSize / HeapRegion::GrainBytes);
_sizer_kind = SizerMaxNewSizeOnly;
}
size_t min_young_region_num() {
return size_to_region_num(_min_gen0_size);
}
size_t initial_young_region_num() {
return size_to_region_num(_initial_gen0_size);
}
size_t max_young_region_num() {
return size_to_region_num(_max_gen0_size);
}
};
}
void G1CollectorPolicy::update_young_list_size_using_newratio(size_t number_of_heap_regions) {
assert(number_of_heap_regions > 0, "Heap must be initialized");
size_t young_size = number_of_heap_regions / (NewRatio + 1);
_min_desired_young_length = young_size;
_max_desired_young_length = young_size;
size_t G1YoungGenSizer::calculate_default_min_length(size_t new_number_of_heap_regions) {
size_t default_value = (new_number_of_heap_regions * G1DefaultMinNewGenPercent) / 100;
return MAX2((size_t)1, default_value);
}
size_t G1YoungGenSizer::calculate_default_max_length(size_t new_number_of_heap_regions) {
size_t default_value = (new_number_of_heap_regions * G1DefaultMaxNewGenPercent) / 100;
return MAX2((size_t)1, default_value);
}
void G1YoungGenSizer::heap_size_changed(size_t new_number_of_heap_regions) {
assert(new_number_of_heap_regions > 0, "Heap must be initialized");
switch (_sizer_kind) {
case SizerDefaults:
_min_desired_young_length = calculate_default_min_length(new_number_of_heap_regions);
_max_desired_young_length = calculate_default_max_length(new_number_of_heap_regions);
break;
case SizerNewSizeOnly:
_max_desired_young_length = calculate_default_max_length(new_number_of_heap_regions);
_max_desired_young_length = MAX2(_min_desired_young_length, _max_desired_young_length);
break;
case SizerMaxNewSizeOnly:
_min_desired_young_length = calculate_default_min_length(new_number_of_heap_regions);
_min_desired_young_length = MIN2(_min_desired_young_length, _max_desired_young_length);
break;
case SizerMaxAndNewSize:
// Do nothing. Values set on the command line, don't update them at runtime.
break;
case SizerNewRatio:
_min_desired_young_length = new_number_of_heap_regions / (NewRatio + 1);
_max_desired_young_length = _min_desired_young_length;
break;
default:
ShouldNotReachHere();
}
assert(_min_desired_young_length <= _max_desired_young_length, "Invalid min/max young gen size values");
}
void G1CollectorPolicy::init() {
@ -468,28 +498,10 @@ void G1CollectorPolicy::init() {
initialize_gc_policy_counters();
G1YoungGenSizer sizer;
_min_desired_young_length = sizer.min_young_region_num();
_max_desired_young_length = sizer.max_young_region_num();
if (FLAG_IS_CMDLINE(NewRatio)) {
if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio");
} else {
// Treat NewRatio as a fixed size that is only recalculated when the heap size changes
update_young_list_size_using_newratio(_g1->n_regions());
_using_new_ratio_calculations = true;
}
}
assert(_min_desired_young_length <= _max_desired_young_length, "Invalid min/max young gen size values");
set_adaptive_young_list_length(_min_desired_young_length < _max_desired_young_length);
if (adaptive_young_list_length()) {
_young_list_fixed_length = 0;
} else {
assert(_min_desired_young_length == _max_desired_young_length, "Min and max young size differ");
_young_list_fixed_length = _min_desired_young_length;
_young_list_fixed_length = _young_gen_sizer->min_desired_young_length();
}
_free_regions_at_end_of_collection = _g1->free_regions();
update_young_list_target_length();
@ -543,11 +555,7 @@ void G1CollectorPolicy::record_new_heap_size(size_t new_number_of_regions) {
// smaller than 1.0) we'll get 1.
_reserve_regions = (size_t) ceil(reserve_regions_d);
if (_using_new_ratio_calculations) {
// -XX:NewRatio was specified so we need to update the
// young gen length when the heap size has changed.
update_young_list_size_using_newratio(new_number_of_regions);
}
_young_gen_sizer->heap_size_changed(new_number_of_regions);
}
size_t G1CollectorPolicy::calculate_young_list_desired_min_length(
@ -565,14 +573,14 @@ size_t G1CollectorPolicy::calculate_young_list_desired_min_length(
}
desired_min_length += base_min_length;
// make sure we don't go below any user-defined minimum bound
return MAX2(_min_desired_young_length, desired_min_length);
return MAX2(_young_gen_sizer->min_desired_young_length(), desired_min_length);
}
size_t G1CollectorPolicy::calculate_young_list_desired_max_length() {
// Here, we might want to also take into account any additional
// constraints (i.e., user-defined minimum bound). Currently, we
// effectively don't set this bound.
return _max_desired_young_length;
return _young_gen_sizer->max_desired_young_length();
}
void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) {

82
hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp
View File

@ -83,6 +83,72 @@ public:
virtual MainBodySummary* main_body_summary() { return this; }
};
// There are three command line options related to the young gen size:
// NewSize, MaxNewSize and NewRatio (There is also -Xmn, but that is
// just a short form for NewSize==MaxNewSize). G1 will use its internal
// heuristics to calculate the actual young gen size, so these options
// basically only limit the range within which G1 can pick a young gen
// size. Also, these are general options taking byte sizes. G1 will
// internally work with a number of regions instead. So, some rounding
// will occur.
//
// If nothing related to the the young gen size is set on the command
// line we should allow the young gen to be between
// G1DefaultMinNewGenPercent and G1DefaultMaxNewGenPercent of the
// heap size. This means that every time the heap size changes the
// limits for the young gen size will be updated.
//
// If only -XX:NewSize is set we should use the specified value as the
// minimum size for young gen. Still using G1DefaultMaxNewGenPercent
// of the heap as maximum.
//
// If only -XX:MaxNewSize is set we should use the specified value as the
// maximum size for young gen. Still using G1DefaultMinNewGenPercent
// of the heap as minimum.
//
// If -XX:NewSize and -XX:MaxNewSize are both specified we use these values.
// No updates when the heap size changes. There is a special case when
// NewSize==MaxNewSize. This is interpreted as "fixed" and will use a
// different heuristic for calculating the collection set when we do mixed
// collection.
//
// If only -XX:NewRatio is set we should use the specified ratio of the heap
// as both min and max. This will be interpreted as "fixed" just like the
// NewSize==MaxNewSize case above. But we will update the min and max
// everytime the heap size changes.
//
// NewSize and MaxNewSize override NewRatio. So, NewRatio is ignored if it is
// combined with either NewSize or MaxNewSize. (A warning message is printed.)
class G1YoungGenSizer : public CHeapObj {
private:
enum SizerKind {
SizerDefaults,
SizerNewSizeOnly,
SizerMaxNewSizeOnly,
SizerMaxAndNewSize,
SizerNewRatio
};
SizerKind _sizer_kind;
size_t _min_desired_young_length;
size_t _max_desired_young_length;
bool _adaptive_size;
size_t calculate_default_min_length(size_t new_number_of_heap_regions);
size_t calculate_default_max_length(size_t new_number_of_heap_regions);
public:
G1YoungGenSizer();
void heap_size_changed(size_t new_number_of_heap_regions);
size_t min_desired_young_length() {
return _min_desired_young_length;
}
size_t max_desired_young_length() {
return _max_desired_young_length;
}
bool adaptive_young_list_length() {
return _adaptive_size;
}
};
class G1CollectorPolicy: public CollectorPolicy {
private:
// either equal to the number of parallel threads, if ParallelGCThreads
@ -167,9 +233,6 @@ private:
// indicates whether we are in young or mixed GC mode
bool _gcs_are_young;
// if true, then it tries to dynamically adjust the length of the
// young list
bool _adaptive_young_list_length;
size_t _young_list_target_length;
size_t _young_list_fixed_length;
size_t _prev_eden_capacity; // used for logging
@ -227,9 +290,7 @@ private:
TruncatedSeq* _young_gc_eff_seq;
bool _using_new_ratio_calculations;
size_t _min_desired_young_length; // as set on the command line or default calculations
size_t _max_desired_young_length; // as set on the command line or default calculations
G1YoungGenSizer* _young_gen_sizer;
size_t _eden_cset_region_length;
size_t _survivor_cset_region_length;
@ -695,8 +756,6 @@ private:
// Count the number of bytes used in the CS.
void count_CS_bytes_used();
void update_young_list_size_using_newratio(size_t number_of_heap_regions);
public:
G1CollectorPolicy();
@ -723,8 +782,6 @@ public:
// This should be called after the heap is resized.
void record_new_heap_size(size_t new_number_of_regions);
public:
void init();
// Create jstat counters for the policy.
@ -1014,10 +1071,7 @@ public:
}
bool adaptive_young_list_length() {
return _adaptive_young_list_length;
}
void set_adaptive_young_list_length(bool adaptive_young_list_length) {
_adaptive_young_list_length = adaptive_young_list_length;
return _young_gen_sizer->adaptive_young_list_length();
}
inline double get_gc_eff_factor() {

10
hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp
View File

@ -289,7 +289,15 @@
\
develop(uintx, G1ConcMarkForceOverflow, 0, \
"The number of times we'll force an overflow during " \
"concurrent marking")
"concurrent marking") \
\
develop(uintx, G1DefaultMinNewGenPercent, 20, \
"Percentage (0-100) of the heap size to use as minimum " \
"young gen size.") \
\
develop(uintx, G1DefaultMaxNewGenPercent, 50, \
"Percentage (0-100) of the heap size to use as maximum " \
"young gen size.")
G1_FLAGS(DECLARE_DEVELOPER_FLAG, DECLARE_PD_DEVELOPER_FLAG, DECLARE_PRODUCT_FLAG, DECLARE_PD_PRODUCT_FLAG, DECLARE_DIAGNOSTIC_FLAG, DECLARE_EXPERIMENTAL_FLAG, DECLARE_NOTPRODUCT_FLAG, DECLARE_MANAGEABLE_FLAG, DECLARE_PRODUCT_RW_FLAG)