counters.h

/*
 * Copyright 2023 Datadog, Inc
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef JAVA_PROFILER_LIBRARY_COUNTERS_H
#define JAVA_PROFILER_LIBRARY_COUNTERS_H

#include "arch.h"
#include <cstring>
#include <vector>

#define DD_COUNTER_TABLE(X)                                                    \
  X(DICTIONARY_BYTES, "dictionary_bytes")                                      \
  X(DICTIONARY_CLASSES_BYTES, "dictionary_classes_bytes")                      \
  X(DICTIONARY_ENDPOINTS_BYTES, "dictionary_endpoints_bytes")                  \
  X(DICTIONARY_CONTEXT_BYTES, "dictionary_context_bytes")                      \
  X(DICTIONARY_PAGES, "dictionary_pages")                                      \
  X(DICTIONARY_CLASSES_PAGES, "dictionary_classes_pages")                      \
  X(DICTIONARY_ENDPOINTS_PAGES, "dictionary_endpoints_pages")                  \
  X(DICTIONARY_CONTEXT_PAGES, "dictionary_context_pages")                      \
  X(DICTIONARY_KEYS, "dictionary_keys")                                        \
  X(DICTIONARY_CLASSES_KEYS, "dictionary_classes_keys")                        \
  X(DICTIONARY_ENDPOINTS_KEYS, "dictionary_endpoints_keys")                    \
  X(DICTIONARY_CONTEXT_KEYS, "dictionary_context_keys")                        \
  X(DICTIONARY_KEYS_BYTES, "dictionary_keys_bytes")                            \
  X(DICTIONARY_CLASSES_KEYS_BYTES, "dictionary_classes_keys_bytes")            \
  X(DICTIONARY_ENDPOINTS_KEYS_BYTES, "dictionary_endpoints_keys_bytes")        \
  X(DICTIONARY_CONTEXT_KEYS_BYTES, "dictionary_context_keys_bytes")            \
  X(DICTIONARY_ARENA_WASTE_BYTES, "dictionary_arena_waste_bytes")              \
  X(DICTIONARY_CLASSES_ARENA_WASTE_BYTES, "dictionary_classes_arena_waste_bytes")     \
  X(DICTIONARY_ENDPOINTS_ARENA_WASTE_BYTES, "dictionary_endpoints_arena_waste_bytes") \
  X(DICTIONARY_CONTEXT_ARENA_WASTE_BYTES, "dictionary_context_arena_waste_bytes")     \
  X(DICTIONARY_DRAIN_TIMEOUTS, "dictionary_drain_timeouts")                    \
  X(CLASS_MAP_AT_CAPACITY, "class_map_at_capacity_drops")                      \
  X(CONTEXT_STORAGE_BYTES, "context_storage_bytes")                            \
  X(CONTEXT_STORAGE_PAGES, "context_storage_pages")                            \
  X(CONTEXT_BOUNDS_MISS_INITS, "context_bounds_miss_inits")                    \
  X(CONTEXT_BOUNDS_MISS_GETS, "context_bounds_miss_gets")                      \
  X(CONTEXT_NULL_PAGE_GETS, "context_null_page_gets")                          \
  X(CONTEXT_ALLOC_FAILS, "context_alloc_fails")                                \
  X(CALLTRACE_STORAGE_BYTES, "calltrace_storage_bytes")                        \
  X(CALLTRACE_STORAGE_TRACES, "calltrace_storage_traces")                      \
  X(LINEAR_ALLOCATOR_BYTES, "linear_allocator_bytes")                          \
  X(LINEAR_ALLOCATOR_CHUNKS, "linear_allocator_chunks")                        \
  X(NATIVE_MEM_LIVE_BYTES, "native_mem_live_bytes")                            \
  X(NATIVE_MEM_MAX_BYTES, "native_mem_max_bytes")                              \
  X(NATIVE_MEM_AVG_BYTES, "native_mem_avg_bytes")                              \
  X(THREAD_IDS_COUNT, "thread_ids_count")                                      \
  X(THREAD_NAMES_COUNT, "thread_names_count")                                  \
  X(THREAD_FILTER_PAGES, "thread_filter_pages")                                \
  X(THREAD_FILTER_BYTES, "thread_filter_bytes")                                \
  X(JMETHODID_SKIPPED, "jmethodid_skipped_count")                              \
  X(CODECACHE_NATIVE_SIZE_BYTES, "codecache_native_size_bytes")                \
  X(CODECACHE_NATIVE_COUNT, "native_codecache_count")                          \
  X(CODECACHE_RUNTIME_STUBS_SIZE_BYTES, "codecache_runtime_stubs_size_bytes")  \
  X(AGCT_NOT_REGISTERED_IN_TLS, "agct_not_registered_in_tls")                  \
  X(AGCT_NOT_JAVA, "agct_not_java")                                            \
  X(AGCT_NATIVE_NO_JAVA_CONTEXT, "agct_native_no_java_context")                \
  X(AGCT_BLOCKED_IN_VM, "agct_blocked_in_vm")                                  \
  X(SKIPPED_WALLCLOCK_UNWINDS, "skipped_wallclock_unwinds")                    \
  X(WC_SIGNAL_SUPPRESSED_SAMPLED_RUN, "wc_signals_suppressed_sampled_run")     \
  X(WC_UNOWNED_BLOCKED_SUPPRESSED, "wc_unowned_blocked_suppressed")            \
  X(WC_UNOWNED_BLOCKED_RECORDED, "wc_unowned_blocked_recorded")                \
  X(WC_SIGNAL_QUEUE_FULL, "wc_signals_queue_full")                             \
  X(UNWINDING_TIME_ASYNC, "unwinding_ticks_async")                             \
  X(UNWINDING_TIME_JVMTI, "unwinding_ticks_jvmti")                             \
  X(CALLTRACE_STORAGE_DROPPED, "calltrace_storage_dropped_traces")             \
  X(CALLTRACE_STORAGE_EXPANSION_SKIPPED, "calltrace_storage_expansion_skipped") \
  X(LINE_NUMBER_TABLES, "line_number_tables")                                  \
  X(LINE_NUMBER_TABLE_UNREADABLE, "line_number_table_unreadable")              \
  X(REMOTE_SYMBOLICATION_FRAMES, "remote_symbolication_frames")                \
  X(REMOTE_SYMBOLICATION_LIBS_WITH_BUILD_ID, "remote_symbolication_libs_with_build_id") \
  X(REMOTE_SYMBOLICATION_BUILD_ID_CACHE_HITS, "remote_symbolication_build_id_cache_hits") \
  X(VTABLE_RECEIVER_RESOLVE_FAILED, "vtable_receiver_resolve_failed")           \
  X(THREAD_ENTRY_MARK_DETECTIONS, "thread_entry_mark_detections")              \
  X(WALKVM_THREAD_INACCESSIBLE, "walkvm_thread_inaccessible")                  \
  X(WALKVM_ANCHOR_NULL, "walkvm_anchor_null")                                  \
  X(WALKVM_CACHED_NOT_JAVA, "walkvm_cached_not_java")                          \
  X(WALKVM_NO_VMTHREAD, "walkvm_no_vmthread")                                  \
  X(WALKVM_VMTHREAD_OK, "walkvm_vmthread_ok")                                  \
  X(WALKVM_ANCHOR_USED_INLINE, "walkvm_anchor_used_inline")                    \
  X(WALKVM_ANCHOR_FALLBACK, "walkvm_anchor_fallback")                          \
  X(WALKVM_CODEH_NO_VM, "walkvm_codeh_no_vm")                                  \
  X(WALKVM_DEPTH_ZERO, "walkvm_depth_zero")                                    \
  X(WALKVM_HIT_CODEHEAP, "walkvm_hit_codeheap")                                \
  X(WALKVM_ANCHOR_FALLBACK_FAIL, "walkvm_anchor_fallback_fail")                \
  X(WALKVM_ANCHOR_CONSUMED, "walkvm_anchor_consumed")                          \
  X(WALKVM_BREAK_INTERPRETED, "walkvm_break_interpreted")                      \
  X(WALKVM_BREAK_COMPILED, "walkvm_break_compiled")                            \
  X(WALKVM_JAVA_FRAME_OK, "walkvm_java_frame_ok")                            \
  X(WALKVM_ANCHOR_INLINE_NO_ANCHOR, "walkvm_anchor_inline_no_anchor")        \
  X(WALKVM_ANCHOR_INLINE_NO_SP, "walkvm_anchor_inline_no_sp")                \
  X(WALKVM_ANCHOR_INLINE_BAD_SP, "walkvm_anchor_inline_bad_sp")              \
  X(WALKVM_SAVED_ANCHOR_USED, "walkvm_saved_anchor_used")                    \
  X(WALKVM_STUB_GENERIC_UNWIND, "walkvm_stub_generic_unwind")                \
  X(WALKVM_STUB_FRAMESIZE_FALLBACK, "walkvm_stub_framesize_fallback")        \
  X(WALKVM_FP_CHAIN_ATTEMPT, "walkvm_fp_chain_attempt")                      \
  X(WALKVM_FP_CHAIN_REACHED_CODEHEAP, "walkvm_fp_chain_reached_codeheap")    \
  X(WALKVM_ANCHOR_NOT_IN_JAVA,  "walkvm_anchor_not_in_java")                   \
  X(WALKVM_CONT_BARRIER_HIT,    "walkvm_cont_barrier_hit")                     \
  X(WALKVM_ENTER_SPECIAL_HIT,   "walkvm_enter_special_hit")                    \
  X(WALKVM_CONT_SPECULATIVE_HIT,"walkvm_cont_speculative_hit")                 \
  X(WALKVM_CONT_ENTRY_NULL,     "walkvm_cont_entry_null")                      \
  X(NATIVE_LIBS_DROPPED, "native_libs_dropped")                                \
  X(SIGACTION_PATCHED_LIBS, "sigaction_patched_libs")                          \
  X(SIGACTION_INTERCEPTED, "sigaction_intercepted")                            \
  X(CTIMER_SIGNAL_OWN, "ctimer_signal_own")                                    \
  X(CTIMER_SIGNAL_FOREIGN, "ctimer_signal_foreign")                            \
  X(WALLCLOCK_SIGNAL_OWN, "wallclock_signal_own")                              \
  X(WALLCLOCK_SIGNAL_FOREIGN, "wallclock_signal_foreign")                      \
  X(JVMTI_STACKS_INIT_OK, "jvmti_stacks_init_ok")                             \
  X(JVMTI_STACKS_INIT_FAILED, "jvmti_stacks_init_failed")                     \
  X(JVMTI_STACKS_REQUESTED, "jvmti_stacks_requested")                         \
  X(NATIVE_TRACE_HOOK_PREFIX_NOT_FOUND, "native_trace_hook_prefix_not_found") \
  X(NATIVE_HOOK_MARK_RESOLVE_FAILED, "native_hook_mark_resolve_failed")       \
  X(JVMTI_STACKS_FAILED_WRONG_PHASE, "jvmti_stacks_failed_wrong_phase")       \
  X(JVMTI_STACKS_FAILED_OTHER, "jvmti_stacks_failed_other")                  \
  /* Delegated stacks dropped at slot-lock. Rec-lock drops from all recording  \
   * paths (delegated and direct) go into SAMPLES_DROPPED_REC_LOCK. */         \
  X(JVMTI_STACKS_DROPPED_LOCK, "jvmti_stacks_dropped_lock")                   \
  X(SAMPLES_DROPPED_REC_LOCK, "samples_dropped_rec_lock")                     \
  X(SAMPLES_DROPPED_THREAD_LOCAL, "samples_dropped_thread_local")             \
  X(SAFECOPY_FAILED, "safecopy_failed")                                       \
  X(SAFEFETCH_FAILED, "safefetch_failed")                                     \
  X(STACKWALK_LONGJMP_RECOVERED, "stackwalk_longjmp_recovered")               \
  /* writeElement() guards against a corrupted/dangling JfrMetadata tree.     \
   * Root cause is still unconfirmed, so these counters are the durable       \
   * signal for spotting a recurrence. */                                     \
  X(METADATA_TREE_NULL_CHILD, "metadata_tree_null_child")                     \
  X(METADATA_TREE_DEPTH_EXCEEDED, "metadata_tree_depth_exceeded")             \
  /* A resolved datadog.ReferenceChain could not be cached in                 \
   * ReferenceChainTracker::_resolved_chains (referenceChains.h): a brand-new \
   * leak-candidate klass arrived with the cache already at                   \
   * MAX_RESOLVED_CHAINS, so its chain is dropped rather than evicting some   \
   * other still-live sample's chain. See that constant's own comment. */     \
  X(REFERENCE_CHAIN_EVENTS_DROPPED, "reference_chain_events_dropped")         \
  /* ReferenceChainTracker::releaseSearchTags() (referenceChains.cpp) failed  \
   * to call GetObjectsWithTags() for at least one batch - the search's tag   \
   * release is retried on a later call rather than proceeding, but this     \
   * counts how often that retry path is taken. */                           \
  X(REFERENCE_CHAIN_TAG_RELEASE_FAILED, "reference_chain_tag_release_failed") \
  /* Profiler::writeReferenceChain() (profiler.cpp) could not acquire a       \
   * sample-record lock within its bounded retry budget and dropped the      \
   * already-dequeued datadog.ReferenceChain event for this dump - not       \
   * permanently lost, since ReferenceChainTracker::_resolved_chains (see    \
   * REFERENCE_CHAIN_EVENTS_DROPPED above) keeps the resolved chain cached   \
   * and re-emits it on a later dump while the leak candidate is still      \
   * live. */                                                                \
  X(REFERENCE_CHAIN_WRITE_DROPPED, "reference_chain_write_dropped")            \
  /* FrontierTable's own calloc/realloc-backed storage (referenceChains.cpp) -   \
   * outside NMT's visibility since it bypasses os::malloc, so this is the only \
   * way to attribute its native RSS contribution. */                          \
  X(REFERENCE_CHAIN_FRONTIER_TABLE_BYTES, "reference_chain_frontier_table_bytes") \
  X(REFERENCE_CHAIN_FRONTIER_TABLE_CAPACITY, "reference_chain_frontier_table_capacity") \
  DD_COUNTER_TABLE_FAULT_INJECTION(X)                                          \
  DD_COUNTER_TABLE_FI_DEBUG(X)                                                 \
  DD_COUNTER_TABLE_DEBUG(X)

// Fault-injection-only counter: number of faults actually injected. Only
// compiled in when __FAULT_INJECTION__ is defined, so it occupies no enum slot
// and adds no storage in normal builds.
#ifdef __FAULT_INJECTION__
#define DD_COUNTER_TABLE_FAULT_INJECTION(X)                                    \
  X(FAULTS_INJECTED, "faults_injected")
#else
#define DD_COUNTER_TABLE_FAULT_INJECTION(X)
#endif

// Fault-injection + debug only: faults injected while the current thread was
// NOT inside a walkVM siglongjmp-protected region. Such a site relies solely on
// safefetch (or would genuinely crash if the poisoned pointer is raw-dereferenced
// outside any recovery), so a non-zero value flags injection sites that are not
// covered by siglongjmp protection. Compiled in only when both __FAULT_INJECTION__
// and DEBUG are defined.
#if defined(__FAULT_INJECTION__) && defined(DEBUG)
#define DD_COUNTER_TABLE_FI_DEBUG(X)                                           \
  X(FAULTS_INJECTED_UNPROTECTED, "faults_injected_unprotected")
#else
#define DD_COUNTER_TABLE_FI_DEBUG(X)
#endif

// Debug-only counters: SafeAccess reads/copies issued while the thread is
// already inside a walkVM siglongjmp-protected region (redundant safefetch
// overhead). Not compiled into release builds at all, so they occupy no enum
// slot and add no storage there.
#ifdef DEBUG
#define DD_COUNTER_TABLE_DEBUG(X)                                             \
  X(SAFEFETCH_WHILE_PROTECTED, "safefetch_while_protected")                   \
  X(SAFECOPY_WHILE_PROTECTED, "safecopy_while_protected")
#else
#define DD_COUNTER_TABLE_DEBUG(X)
#endif

#define X_ENUM(a, b) a,
typedef enum CounterId : int {
  DD_COUNTER_TABLE(X_ENUM) DD_NUM_COUNTERS
} CounterId;
#undef X_ENUM

class Counters {
private:
  static const u32 ALIGNMENT = 16;
  volatile long long *_counters;
  static long long *init();
  Counters() : _counters() {
#ifdef COUNTERS
    _counters = Counters::init();
#endif // COUNTERS
  }

public:
  static Counters &instance() {
    static Counters instance;
    return instance;
  }

  Counters(Counters const &) = delete;
  void operator=(Counters const &) = delete;

  static constexpr int address(int index) { return index * ALIGNMENT; }

  static constexpr int size() {
    return address(DD_NUM_COUNTERS * sizeof(long long));
  }

  static long long *getCounters() {
#ifdef COUNTERS
    return const_cast<long long *>(Counters::instance()._counters);
#else
    return nullptr;
#endif // COUNTERS
  }

  static long long getCounter(CounterId counter, int offset = 0) {
#ifdef COUNTERS
    return Counters::instance()
        ._counters[address(static_cast<int>(counter) + offset)];
#else
    return 0;
#endif // COUNTERS
  }

  static void set(CounterId counter, long long value, int offset = 0) {
#ifdef COUNTERS
    storeRelease(Counters::instance()
                     ._counters[address(static_cast<int>(counter) + offset)],
                 value);
#endif // COUNTERS
  }

  static void increment(CounterId counter, long long delta = 1,
                        int offset = 0) {
#ifdef COUNTERS
    atomicIncRelaxed(Counters::instance()
                         ._counters[address(static_cast<int>(counter) + offset)],
                     delta);
#endif // COUNTERS
  }

  static void decrement(CounterId counter, long long delta = 1,
                        int offset = 0) {
#ifdef COUNTERS
    increment(counter, -delta, offset);
#endif // COUNTERS
  }

  static std::vector<const char *> describeCounters() {
#ifdef COUNTERS
#define X_NAME(a, b) b,
    return {DD_COUNTER_TABLE(X_NAME)};
#undef X_NAME
#else
    return {};
#endif // COUNTERS
  }

  static void reset() {
#ifdef COUNTERS
    memset((void *)Counters::instance()._counters, 0, size());
#endif // COUNTERS
  }
};

#endif // JAVA_PROFILER_LIBRARY_COUNTERS_H