xo-alloc/include/xo/alloc/GcStatistics.hpp

217 lines
8.7 KiB
C++

/* GcStatistics.hpp
*
* author: Roland Conybeare, Aug 2025
*/
#pragma once
#include "generation.hpp"
#include "CircularBuffer.hpp"
#include "xo/reflect/TypeDescr.hpp"
#include "xo/indentlog/print/pretty.hpp"
#include <ostream>
#include <array>
namespace xo {
namespace gc {
/** @class PerGenerationStatistics
* @brief garbage collection statistics for particular GC generation
**/
class PerGenerationStatistics {
public:
/** update statistics after a GC cycle
* @param alloc_z. new allocations (since preceding GC)
* @param before_z. generation size (bytes allocated) before collection
* @param after_z. generation size after collection
* @param promote_z. bytes promoted to next generation
**/
void include_gc(std::size_t alloc_z, std::size_t before_z, std::size_t after_z,
std::size_t promote_z);
/** update with current state (use at end of gc cycle) **/
void update_snapshot(std::size_t after_z);
/** @param os. write stats on this output stream **/
void display(std::ostream & os) const;
/** number of bytes currently in use **/
std::size_t used_z_ = 0;
/** number of collection cycles completed **/
std::size_t n_gc_ = 0;
/** sum of new alloc bytes, sampled at start of each collection cycle **/
std::size_t new_alloc_z_ = 0;
/** sum of allocated bytes sampled at beginning of each collection cycle **/
std::size_t scanned_z_ = 0;
/** sum of bytes remaining after collection cycle **/
std::size_t survive_z_ = 0;
/** sum of bytes promoted to next generation **/
std::size_t promote_z_ = 0;
};
inline std::ostream & operator<< (std::ostream & os, const PerGenerationStatistics & x) {
x.display(os);
return os;
}
/** @class GcStatistics
* @brief garbage collection statistics
**/
class GcStatistics {
public:
GcStatistics() = default;
/** update statistics after a GC cycle
* @param upto. nursery -> incremental collection; tenured -> full collection
* @param alloc_z. new allocations (since preceding GC)
* @param before_z. generation size (bytes allocated) before collection
* @param after_z. generation size after collection
* @param promote_z. bytes promoted to next generation
**/
void include_gc(generation upto, std::size_t alloc_z,
std::size_t before_z, std::size_t after_z, std::size_t promote_z);
/** update snapshot for current state.
* Use with tenured stats after incremental gc
**/
void update_snapshot(generation upto, std::size_t after_z);
/** @param os. write stats on this output stream **/
void display(std::ostream & os) const;
/** statistics gathered across {incr, full} GCs respectively **/
std::array<PerGenerationStatistics, static_cast<std::size_t>(generation::N)> gen_v_;
/** total bytes allocated since inception **/
std::size_t total_allocated_ = 0;
/** snapshot of total bytes promoted asof beginning of last gc cycle **/
std::size_t total_promoted_sab_ = 0;
/** total bytes promoted from nursery->tenured since inception **/
std::size_t total_promoted_ = 0;
/** total number of mutations to already-allocated objects,
* whether or not GC needs to log them.
**/
std::size_t n_mutation_ = 0;
/** total number of mutation eligible for logging (cumulative across GCs) **/
std::size_t n_logged_mutation_ = 0;
/** total number of cross-generation mutations
* (tenured->nursery when reported; cumulative across GCs) **/
std::size_t n_xgen_mutation_ = 0;
/** total number of cross-checkpoint mutations
* (N0 -> N1 when reported; cumulative across GCs)
**/
std::size_t n_xckp_mutation_ = 0;
};
inline std::ostream & operator<< (std::ostream & os, const GcStatistics & x) {
x.display(os);
return os;
}
/** @class GcStatisticsExt
* @brief extend GcStatistics for application convenience
**/
class GcStatisticsExt : public GcStatistics {
public:
GcStatisticsExt() = default;
explicit GcStatisticsExt(const GcStatistics & x) : GcStatistics{x} {}
/** @param os. write stats on this output stream **/
void display(std::ostream & os) const;
/** current capacity of nursery generation **/
std::size_t nursery_z_ = 0;
/** current nursery survivor size **/
std::size_t nursery_before_checkpoint_z_ = 0;
/** current nursery new alloc size **/
std::size_t nursery_after_checkpoint_z_ = 0;
/** current capacity of tenured generation **/
std::size_t tenured_z_ = 0;
};
inline std::ostream & operator<< (std::ostream & os, const GcStatisticsExt & x) {
x.display(os);
return os;
}
/** @class GcStatisticsHistoryItem
* @brief info we want to record over time (won't have cumulative things in it)
**/
class GcStatisticsHistoryItem {
public:
GcStatisticsHistoryItem() = default;
GcStatisticsHistoryItem(generation upto,
std::size_t new_alloc_z,
std::size_t survive_z,
std::size_t promote_z,
std::size_t persist_z,
std::size_t effort_z,
std::size_t garbage0_z,
std::size_t garbage1_z,
std::size_t garbageN_z)
: upto_{upto},
new_alloc_z_{new_alloc_z},
survive_z_{survive_z},
promote_z_{promote_z},
persist_z_{persist_z},
effort_z_{effort_z},
garbage0_z_{garbage0_z},
garbage1_z_{garbage1_z},
garbageN_z_{garbageN_z}
{}
/** @param os. write stats on this output stream **/
void display(std::ostream & os) const;
/** type of GC that generated this record **/
generation upto_;
/** #of bytes new allocation **/
std::size_t new_alloc_z_ = 0;
/** #of bytes surviving their first collection (i.e. N0->N1) **/
std::size_t survive_z_ = 0;
/** #of bytes promoted to tenured.
* Comprises all objects surviving their 2nd collection (i.e. N1->T)
**/
std::size_t promote_z_ = 0;
/** #of bytes surviving 3rd of later collection **/
std::size_t persist_z_ = 0;
/** #of bytes copied **/
std::size_t effort_z_ = 0;
/** #of bytes garbage from N0 (i.e. survived 0 GCs) **/
std::size_t garbage0_z_ = 0;
/** #of bytes garbage from N1 (i.e. survived 1 GCs) **/
std::size_t garbage1_z_ = 0;
/** #of bytes garbage from T (i.e. survived 2+ GCs) **/
std::size_t garbageN_z_ = 0;
};
inline std::ostream & operator<< (std::ostream & os, const GcStatisticsHistoryItem & x) {
x.display(os);
return os;
}
using GcStatisticsHistory = CircularBuffer<GcStatisticsHistoryItem>;
} /*namespace gc*/
namespace print {
template <>
struct ppdetail<xo::gc::PerGenerationStatistics> {
static bool print_pretty(const ppindentinfo &, const xo::gc::PerGenerationStatistics &);
};
template<>
struct ppdetail<xo::gc::GcStatistics> {
static bool print_pretty(const ppindentinfo &, const xo::gc::GcStatistics &);
};
template<>
struct ppdetail<xo::gc::GcStatisticsExt> {
static bool print_pretty(const ppindentinfo &, const xo::gc::GcStatisticsExt &);
};
template<>
struct ppdetail<xo::gc::GcStatisticsHistoryItem> {
static bool print_pretty(const ppindentinfo &, const xo::gc::GcStatisticsHistoryItem &);
};
} /*namespace print*/
} /*namespace xo*/
/* end GcStatistics.hpp */