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#include "precompiled.hpp"
#include "gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp"
#include "gc/shenandoah/shenandoahCollectionSet.hpp"
#include "gc/shenandoah/shenandoahFreeSet.hpp"
! #include "gc/shenandoah/shenandoahHeap.inline.hpp"
#include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
#include "logging/log.hpp"
#include "logging/logTag.hpp"
#include "utilities/quickSort.hpp"
#include "precompiled.hpp"
#include "gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp"
#include "gc/shenandoah/shenandoahCollectionSet.hpp"
#include "gc/shenandoah/shenandoahFreeSet.hpp"
! #include "gc/shenandoah/shenandoahGeneration.hpp"
#include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
#include "logging/log.hpp"
#include "logging/logTag.hpp"
#include "utilities/quickSort.hpp"
// that the true value of our estimate is outside the interval. These are used
// as bounds on the adjustments applied at the outcome of a GC cycle.
const double ShenandoahAdaptiveHeuristics::MINIMUM_CONFIDENCE = 0.319; // 25%
const double ShenandoahAdaptiveHeuristics::MAXIMUM_CONFIDENCE = 3.291; // 99.9%
! ShenandoahAdaptiveHeuristics::ShenandoahAdaptiveHeuristics() :
! ShenandoahHeuristics(),
_margin_of_error_sd(ShenandoahAdaptiveInitialConfidence),
_spike_threshold_sd(ShenandoahAdaptiveInitialSpikeThreshold),
_last_trigger(OTHER) { }
ShenandoahAdaptiveHeuristics::~ShenandoahAdaptiveHeuristics() {}
// that the true value of our estimate is outside the interval. These are used
// as bounds on the adjustments applied at the outcome of a GC cycle.
const double ShenandoahAdaptiveHeuristics::MINIMUM_CONFIDENCE = 0.319; // 25%
const double ShenandoahAdaptiveHeuristics::MAXIMUM_CONFIDENCE = 3.291; // 99.9%
! ShenandoahAdaptiveHeuristics::ShenandoahAdaptiveHeuristics(ShenandoahGeneration* generation) :
! ShenandoahHeuristics(generation),
_margin_of_error_sd(ShenandoahAdaptiveInitialConfidence),
_spike_threshold_sd(ShenandoahAdaptiveInitialSpikeThreshold),
_last_trigger(OTHER) { }
ShenandoahAdaptiveHeuristics::~ShenandoahAdaptiveHeuristics() {}
// Therefore, we start by sorting the regions by garbage. Then we unconditionally add the best candidates
// before we meet min_garbage. Then we add all candidates that fit with a garbage threshold before
// we hit max_cset. When max_cset is hit, we terminate the cset selection. Note that in this scheme,
// ShenandoahGarbageThreshold is the soft threshold which would be ignored until min_garbage is hit.
! size_t capacity = ShenandoahHeap::heap()->soft_max_capacity();
size_t max_cset = (size_t)((1.0 * capacity / 100 * ShenandoahEvacReserve) / ShenandoahEvacWaste);
size_t free_target = (capacity / 100 * ShenandoahMinFreeThreshold) + max_cset;
size_t min_garbage = (free_target > actual_free ? (free_target - actual_free) : 0);
log_info(gc, ergo)("Adaptive CSet Selection. Target Free: " SIZE_FORMAT "%s, Actual Free: "
// Therefore, we start by sorting the regions by garbage. Then we unconditionally add the best candidates
// before we meet min_garbage. Then we add all candidates that fit with a garbage threshold before
// we hit max_cset. When max_cset is hit, we terminate the cset selection. Note that in this scheme,
// ShenandoahGarbageThreshold is the soft threshold which would be ignored until min_garbage is hit.
! size_t capacity = _generation->soft_max_capacity();
size_t max_cset = (size_t)((1.0 * capacity / 100 * ShenandoahEvacReserve) / ShenandoahEvacWaste);
size_t free_target = (capacity / 100 * ShenandoahMinFreeThreshold) + max_cset;
size_t min_garbage = (free_target > actual_free ? (free_target - actual_free) : 0);
log_info(gc, ergo)("Adaptive CSet Selection. Target Free: " SIZE_FORMAT "%s, Actual Free: "
static double saturate(double value, double min, double max) {
return MAX2(MIN2(value, max), min);
}
bool ShenandoahAdaptiveHeuristics::should_start_gc() {
! ShenandoahHeap* heap = ShenandoahHeap::heap();
! size_t max_capacity = heap->max_capacity();
! size_t capacity = heap->soft_max_capacity();
! size_t available = heap->free_set()->available();
! size_t allocated = heap->bytes_allocated_since_gc_start();
// Make sure the code below treats available without the soft tail.
size_t soft_tail = max_capacity - capacity;
available = (available > soft_tail) ? (available - soft_tail) : 0;
// Track allocation rate even if we decide to start a cycle for other reasons.
double rate = _allocation_rate.sample(allocated);
_last_trigger = OTHER;
size_t min_threshold = capacity / 100 * ShenandoahMinFreeThreshold;
if (available < min_threshold) {
! log_info(gc)("Trigger: Free (" SIZE_FORMAT "%s) is below minimum threshold (" SIZE_FORMAT "%s)",
byte_size_in_proper_unit(available), proper_unit_for_byte_size(available),
byte_size_in_proper_unit(min_threshold), proper_unit_for_byte_size(min_threshold));
return true;
}
const size_t max_learn = ShenandoahLearningSteps;
if (_gc_times_learned < max_learn) {
size_t init_threshold = capacity / 100 * ShenandoahInitFreeThreshold;
if (available < init_threshold) {
! log_info(gc)("Trigger: Learning " SIZE_FORMAT " of " SIZE_FORMAT ". Free (" SIZE_FORMAT "%s) is below initial threshold (" SIZE_FORMAT "%s)",
! _gc_times_learned + 1, max_learn,
byte_size_in_proper_unit(available), proper_unit_for_byte_size(available),
byte_size_in_proper_unit(init_threshold), proper_unit_for_byte_size(init_threshold));
return true;
}
}
static double saturate(double value, double min, double max) {
return MAX2(MIN2(value, max), min);
}
bool ShenandoahAdaptiveHeuristics::should_start_gc() {
! size_t max_capacity = _generation->max_capacity();
! size_t capacity = _generation->soft_max_capacity();
! size_t available = _generation->available();
! size_t allocated = _generation->bytes_allocated_since_gc_start();
!
+ log_debug(gc)("should_start_gc (%s)? available: " SIZE_FORMAT ", soft_max_capacity: " SIZE_FORMAT
+ ", max_capacity: " SIZE_FORMAT ", allocated: " SIZE_FORMAT,
+ _generation->name(), available, capacity, max_capacity, allocated);
// Make sure the code below treats available without the soft tail.
size_t soft_tail = max_capacity - capacity;
available = (available > soft_tail) ? (available - soft_tail) : 0;
// Track allocation rate even if we decide to start a cycle for other reasons.
double rate = _allocation_rate.sample(allocated);
_last_trigger = OTHER;
size_t min_threshold = capacity / 100 * ShenandoahMinFreeThreshold;
+
+ log_debug(gc)(" available adjusted to: " SIZE_FORMAT ", min_threshold: " SIZE_FORMAT ", ShenandoahMinFreeThreshold: " SIZE_FORMAT,
+ available, min_threshold, ShenandoahMinFreeThreshold);
+
if (available < min_threshold) {
! log_info(gc)("Trigger (%s): Free (" SIZE_FORMAT "%s) is below minimum threshold (" SIZE_FORMAT "%s)",
+ _generation->name(),
byte_size_in_proper_unit(available), proper_unit_for_byte_size(available),
byte_size_in_proper_unit(min_threshold), proper_unit_for_byte_size(min_threshold));
return true;
}
+ // Check if we need to learn a bit about the application
const size_t max_learn = ShenandoahLearningSteps;
if (_gc_times_learned < max_learn) {
size_t init_threshold = capacity / 100 * ShenandoahInitFreeThreshold;
if (available < init_threshold) {
! log_info(gc)("Trigger (%s): Learning " SIZE_FORMAT " of " SIZE_FORMAT ". Free (" SIZE_FORMAT "%s) is below initial threshold (" SIZE_FORMAT "%s)",
! _generation->name(), _gc_times_learned + 1, max_learn,
byte_size_in_proper_unit(available), proper_unit_for_byte_size(available),
byte_size_in_proper_unit(init_threshold), proper_unit_for_byte_size(init_threshold));
return true;
}
}
allocation_headroom -= MIN2(allocation_headroom, spike_headroom);
allocation_headroom -= MIN2(allocation_headroom, penalties);
double avg_cycle_time = _gc_time_history->davg() + (_margin_of_error_sd * _gc_time_history->dsd());
double avg_alloc_rate = _allocation_rate.upper_bound(_margin_of_error_sd);
if (avg_cycle_time > allocation_headroom / avg_alloc_rate) {
! log_info(gc)("Trigger: Average GC time (%.2f ms) is above the time for average allocation rate (%.0f %sB/s) to deplete free headroom (" SIZE_FORMAT "%s) (margin of error = %.2f)",
! avg_cycle_time * 1000,
byte_size_in_proper_unit(avg_alloc_rate), proper_unit_for_byte_size(avg_alloc_rate),
byte_size_in_proper_unit(allocation_headroom), proper_unit_for_byte_size(allocation_headroom),
_margin_of_error_sd);
log_info(gc, ergo)("Free headroom: " SIZE_FORMAT "%s (free) - " SIZE_FORMAT "%s (spike) - " SIZE_FORMAT "%s (penalties) = " SIZE_FORMAT "%s",
allocation_headroom -= MIN2(allocation_headroom, spike_headroom);
allocation_headroom -= MIN2(allocation_headroom, penalties);
double avg_cycle_time = _gc_time_history->davg() + (_margin_of_error_sd * _gc_time_history->dsd());
double avg_alloc_rate = _allocation_rate.upper_bound(_margin_of_error_sd);
+ log_debug(gc)("%s: average GC time: %.2f ms, allocation rate: %.0f %s/s",
+ _generation->name(), avg_cycle_time * 1000, byte_size_in_proper_unit(avg_alloc_rate), proper_unit_for_byte_size(avg_alloc_rate));
+
if (avg_cycle_time > allocation_headroom / avg_alloc_rate) {
! log_info(gc)("Trigger (%s): Average GC time (%.2f ms) is above the time for average allocation rate (%.0f %sB/s) to deplete free headroom (" SIZE_FORMAT "%s) (margin of error = %.2f)",
! _generation->name(), avg_cycle_time * 1000,
byte_size_in_proper_unit(avg_alloc_rate), proper_unit_for_byte_size(avg_alloc_rate),
byte_size_in_proper_unit(allocation_headroom), proper_unit_for_byte_size(allocation_headroom),
_margin_of_error_sd);
log_info(gc, ergo)("Free headroom: " SIZE_FORMAT "%s (free) - " SIZE_FORMAT "%s (spike) - " SIZE_FORMAT "%s (penalties) = " SIZE_FORMAT "%s",
return true;
}
bool is_spiking = _allocation_rate.is_spiking(rate, _spike_threshold_sd);
if (is_spiking && avg_cycle_time > allocation_headroom / rate) {
! log_info(gc)("Trigger: Average GC time (%.2f ms) is above the time for instantaneous allocation rate (%.0f %sB/s) to deplete free headroom (" SIZE_FORMAT "%s) (spike threshold = %.2f)",
! avg_cycle_time * 1000,
byte_size_in_proper_unit(rate), proper_unit_for_byte_size(rate),
byte_size_in_proper_unit(allocation_headroom), proper_unit_for_byte_size(allocation_headroom),
_spike_threshold_sd);
_last_trigger = SPIKE;
return true;
return true;
}
bool is_spiking = _allocation_rate.is_spiking(rate, _spike_threshold_sd);
if (is_spiking && avg_cycle_time > allocation_headroom / rate) {
! log_info(gc)("Trigger (%s): Average GC time (%.2f ms) is above the time for instantaneous allocation rate (%.0f %sB/s) to deplete free headroom (" SIZE_FORMAT "%s) (spike threshold = %.2f)",
! _generation->name(), avg_cycle_time * 1000,
byte_size_in_proper_unit(rate), proper_unit_for_byte_size(rate),
byte_size_in_proper_unit(allocation_headroom), proper_unit_for_byte_size(allocation_headroom),
_spike_threshold_sd);
_last_trigger = SPIKE;
return true;
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