Panda3D
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A basic LRU-type algorithm, except that it is adaptive and attempts to avoid evicting pages that have been used more frequently (even if less recently) than other pages. More...
#include "adaptiveLru.h"
Public Types | |
enum | LruPagePriority { LPP_Highest = 0, LPP_High = 10, LPP_New = 20, LPP_Normal = 25, LPP_Intermediate = 30, LPP_Low = 40, LPP_TotalPriorities = 50 } |
Public Member Functions | |
AdaptiveLru (const string &name, size_t max_size) | |
void | begin_epoch () |
Marks the end of the previous epoch and the beginning of the next one. More... | |
PN_stdfloat | calculate_exponential_moving_average (PN_stdfloat value, PN_stdfloat average) const |
void | consider_evict () |
Evicts a sequence of objects if the queue is full. More... | |
size_t | count_active_size () const |
Returns the total size of the pages that were enqueued since the last call to begin_epoch(). More... | |
void | do_access_page (AdaptiveLruPage *page) |
Marks a page accessed. More... | |
void | do_add_page (AdaptiveLruPage *page) |
Adds a new page the the LRU. More... | |
void | do_evict_to (size_t target_size, bool hard_evict) |
Evicts pages until the LRU is within the indicated size. More... | |
void | do_partial_lru_update (int num_updates) |
This only updates a number of pages up to the specified maximum_updates. More... | |
void | do_remove_page (AdaptiveLruPage *page) |
Removes a page from the LRU. More... | |
bool | do_validate () |
Checks that the LRU is internally consistent. More... | |
void | evict_to (size_t target_size) |
Evicts a sequence of objects until the queue fits within the indicated target size, regardless of its normal max size. More... | |
size_t | get_max_size () const |
Returns the max size of all objects that are allowed to be active on the LRU. More... | |
int | get_max_updates_per_frame () const |
Returns the maximum number of pages the AdaptiveLru will update each frame. More... | |
size_t | get_total_size () const |
Returns the total size of all objects currently active on the LRU. More... | |
PN_stdfloat | get_weight () const |
Returns the weight value used to compute the exponential moving average. More... | |
void | output (ostream &out) const |
void | set_max_size (size_t max_size) |
Changes the max size of all objects that are allowed to be active on the LRU. More... | |
void | set_max_updates_per_frame (int max_updates_per_frame) |
Specifies the maximum number of pages the AdaptiveLru will update each frame. More... | |
void | set_weight (PN_stdfloat weight) |
Specifies the weight value used to compute the exponential moving average. More... | |
void | update_page (AdaptiveLruPage *page) |
This updates the page's average utilization. More... | |
bool | validate () |
Checks that the LRU is internally self-consistent. More... | |
void | write (ostream &out, int indent_level) const |
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Namable (const string &initial_name="") | |
Namable (const Namable ©) | |
void | clear_name () |
Resets the Namable's name to empty. More... | |
const string & | get_name () const |
bool | has_name () const |
Returns true if the Namable has a nonempty name set, false if the name is empty. More... | |
Namable & | operator= (const Namable &other) |
void | output (ostream &out) const |
Outputs the Namable. More... | |
void | set_name (const string &name) |
Public Attributes | |
unsigned int | _current_frame_identifier |
LightMutex | _lock |
size_t | _max_size |
int | _max_updates_per_frame |
AdaptiveLruPageDynamicList | _page_array [LPP_TotalPriorities] |
AdaptiveLruPageStaticList | _static_list |
size_t | _total_size |
double | _weight |
Friends | |
class | AdaptiveLruPage |
Additional Inherited Members | |
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static TypeHandle | get_class_type () |
static void | init_type () |
A basic LRU-type algorithm, except that it is adaptive and attempts to avoid evicting pages that have been used more frequently (even if less recently) than other pages.
The interface is designed to be identical to that for SimpleLru, so that it may be used as a drop-in replacement.
Definition at line 49 of file adaptiveLru.h.
void AdaptiveLru::begin_epoch | ( | ) |
Marks the end of the previous epoch and the beginning of the next one.
This will evict any objects that are pending eviction, and also update any internal bookkeeping.
Definition at line 237 of file adaptiveLru.cxx.
References do_add_page(), ClockObject::get_frame_count(), and ClockObject::get_global_clock().
Referenced by count_active_size(), and AdaptiveLruPage::get_num_inactive_frames().
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inline |
Evicts a sequence of objects if the queue is full.
Definition at line 63 of file adaptiveLru.I.
References do_evict_to(), and evict_to().
Referenced by set_max_size().
size_t AdaptiveLru::count_active_size | ( | ) | const |
Returns the total size of the pages that were enqueued since the last call to begin_epoch().
Definition at line 213 of file adaptiveLru.cxx.
References begin_epoch().
Referenced by AdaptiveLruPage::enqueue_lru().
void AdaptiveLru::do_access_page | ( | AdaptiveLruPage * | page | ) |
Marks a page accessed.
Definition at line 334 of file adaptiveLru.cxx.
References do_evict_to().
Referenced by do_remove_page(), and AdaptiveLruPage::enqueue_lru().
void AdaptiveLru::do_add_page | ( | AdaptiveLruPage * | page | ) |
Adds a new page the the LRU.
Definition at line 304 of file adaptiveLru.cxx.
References do_remove_page().
Referenced by begin_epoch().
void AdaptiveLru::do_evict_to | ( | size_t | target_size, |
bool | hard_evict | ||
) |
Evicts pages until the LRU is within the indicated size.
Assumes the lock is already held. If hard_evict is false, does not evict "active" pages that were added within this epoch.
Definition at line 366 of file adaptiveLru.cxx.
References do_validate(), and AdaptiveLruPage::evict_lru().
Referenced by consider_evict(), do_access_page(), evict_to(), and set_max_size().
void AdaptiveLru::do_partial_lru_update | ( | int | num_updates | ) |
This only updates a number of pages up to the specified maximum_updates.
Assumes the lock is held.
Definition at line 80 of file adaptiveLru.cxx.
References update_page().
void AdaptiveLru::do_remove_page | ( | AdaptiveLruPage * | page | ) |
Removes a page from the LRU.
Definition at line 319 of file adaptiveLru.cxx.
References do_access_page().
Referenced by do_add_page().
bool AdaptiveLru::do_validate | ( | ) |
Checks that the LRU is internally consistent.
Assume the lock is already held.
Definition at line 421 of file adaptiveLru.cxx.
References AdaptiveLruPage::evict_lru(), and AdaptiveLruPage::get_lru_size().
Referenced by do_evict_to(), and validate().
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inline |
Evicts a sequence of objects until the queue fits within the indicated target size, regardless of its normal max size.
Definition at line 78 of file adaptiveLru.I.
References do_evict_to(), and validate().
Referenced by consider_evict().
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inline |
Returns the max size of all objects that are allowed to be active on the LRU.
Definition at line 35 of file adaptiveLru.I.
References set_max_size().
Referenced by PreparedGraphicsObjects::get_graphics_memory_limit(), and get_total_size().
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inline |
Returns the maximum number of pages the AdaptiveLru will update each frame.
Definition at line 140 of file adaptiveLru.I.
References AdaptiveLruPage::get_lru().
Referenced by set_max_updates_per_frame().
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inline |
Returns the total size of all objects currently active on the LRU.
Definition at line 23 of file adaptiveLru.I.
References get_max_size().
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inline |
Returns the weight value used to compute the exponential moving average.
Definition at line 116 of file adaptiveLru.I.
References set_max_updates_per_frame().
Referenced by set_weight().
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inline |
Changes the max size of all objects that are allowed to be active on the LRU.
If the size is (size_t)-1, there is no limit.
Definition at line 49 of file adaptiveLru.I.
References consider_evict(), and do_evict_to().
Referenced by get_max_size().
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inline |
Specifies the maximum number of pages the AdaptiveLru will update each frame.
This is a performance optimization: keeping this number low limits the impact of the AdaptiveLru's adaptive algorithm.
Definition at line 129 of file adaptiveLru.I.
References get_max_updates_per_frame().
Referenced by get_weight().
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inline |
Specifies the weight value used to compute the exponential moving average.
Definition at line 105 of file adaptiveLru.I.
References get_weight().
Referenced by validate().
void AdaptiveLru::update_page | ( | AdaptiveLruPage * | page | ) |
This updates the page's average utilization.
Priority LPP_New is considered to be average usage of 1.0 (which means the page is used once per frame on average). Priorities < LPP_New are for pages used more than once per frame and Priorities > LPP_New are for pages used less than once per frame.
Assumes the lock is held.
Definition at line 119 of file adaptiveLru.cxx.
References AdaptiveLruPage::enqueue_lru().
Referenced by do_partial_lru_update().
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inline |
Checks that the LRU is internally self-consistent.
Returns true if successful, false if there is some problem.
Definition at line 93 of file adaptiveLru.I.
References do_validate(), and set_weight().
Referenced by evict_to(), and AdaptiveLruPage::get_num_inactive_frames().