1 files changed, 354 insertions, 0 deletions
diff --git a/src/rocksdb/utilities/simulator_cache/sim_cache.cc b/src/rocksdb/utilities/simulator_cache/sim_cache.cc
new file mode 100644
index 000000000..ec411cf9a
--- /dev/null
+++ b/src/rocksdb/utilities/simulator_cache/sim_cache.cc
@@ -0,0 +1,354 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#include "rocksdb/utilities/sim_cache.h"
+#include <atomic>
+#include "env/composite_env_wrapper.h"
+#include "file/writable_file_writer.h"
+#include "monitoring/statistics.h"
+#include "port/port.h"
+#include "rocksdb/env.h"
+#include "util/mutexlock.h"
+#include "util/string_util.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+namespace {
+
+class CacheActivityLogger {
+ public:
+  CacheActivityLogger()
+      : activity_logging_enabled_(false), max_logging_size_(0) {}
+
+  ~CacheActivityLogger() {
+    MutexLock l(&mutex_);
+
+    StopLoggingInternal();
+  }
+
+  Status StartLogging(const std::string& activity_log_file, Env* env,
+                      uint64_t max_logging_size = 0) {
+    assert(activity_log_file != "");
+    assert(env != nullptr);
+
+    Status status;
+    EnvOptions env_opts;
+    std::unique_ptr<WritableFile> log_file;
+
+    MutexLock l(&mutex_);
+
+    // Stop existing logging if any
+    StopLoggingInternal();
+
+    // Open log file
+    status = env->NewWritableFile(activity_log_file, &log_file, env_opts);
+    if (!status.ok()) {
+      return status;
+    }
+    file_writer_.reset(new WritableFileWriter(
+        NewLegacyWritableFileWrapper(std::move(log_file)), activity_log_file,
+        env_opts));
+
+    max_logging_size_ = max_logging_size;
+    activity_logging_enabled_.store(true);
+
+    return status;
+  }
+
+  void StopLogging() {
+    MutexLock l(&mutex_);
+
+    StopLoggingInternal();
+  }
+
+  void ReportLookup(const Slice& key) {
+    if (activity_logging_enabled_.load() == false) {
+      return;
+    }
+
+    std::string log_line = "LOOKUP - " + key.ToString(true) + "\n";
+
+    // line format: "LOOKUP - <KEY>"
+    MutexLock l(&mutex_);
+    Status s = file_writer_->Append(log_line);
+    if (!s.ok() && bg_status_.ok()) {
+      bg_status_ = s;
+    }
+    if (MaxLoggingSizeReached() || !bg_status_.ok()) {
+      // Stop logging if we have reached the max file size or
+      // encountered an error
+      StopLoggingInternal();
+    }
+  }
+
+  void ReportAdd(const Slice& key, size_t size) {
+    if (activity_logging_enabled_.load() == false) {
+      return;
+    }
+
+    std::string log_line = "ADD - ";
+    log_line += key.ToString(true);
+    log_line += " - ";
+    AppendNumberTo(&log_line, size);
+  // @lint-ignore TXT2 T25377293 Grandfathered in
+		log_line += "\n";
+
+    // line format: "ADD - <KEY> - <KEY-SIZE>"
+    MutexLock l(&mutex_);
+    Status s = file_writer_->Append(log_line);
+    if (!s.ok() && bg_status_.ok()) {
+      bg_status_ = s;
+    }
+
+    if (MaxLoggingSizeReached() || !bg_status_.ok()) {
+      // Stop logging if we have reached the max file size or
+      // encountered an error
+      StopLoggingInternal();
+    }
+  }
+
+  Status& bg_status() {
+    MutexLock l(&mutex_);
+    return bg_status_;
+  }
+
+ private:
+  bool MaxLoggingSizeReached() {
+    mutex_.AssertHeld();
+
+    return (max_logging_size_ > 0 &&
+            file_writer_->GetFileSize() >= max_logging_size_);
+  }
+
+  void StopLoggingInternal() {
+    mutex_.AssertHeld();
+
+    if (!activity_logging_enabled_) {
+      return;
+    }
+
+    activity_logging_enabled_.store(false);
+    Status s = file_writer_->Close();
+    if (!s.ok() && bg_status_.ok()) {
+      bg_status_ = s;
+    }
+  }
+
+  // Mutex to sync writes to file_writer, and all following
+  // class data members
+  port::Mutex mutex_;
+  // Indicates if logging is currently enabled
+  // atomic to allow reads without mutex
+  std::atomic<bool> activity_logging_enabled_;
+  // When reached, we will stop logging and close the file
+  // Value of 0 means unlimited
+  uint64_t max_logging_size_;
+  std::unique_ptr<WritableFileWriter> file_writer_;
+  Status bg_status_;
+};
+
+// SimCacheImpl definition
+class SimCacheImpl : public SimCache {
+ public:
+  // capacity for real cache (ShardedLRUCache)
+  // test_capacity for key only cache
+  SimCacheImpl(std::shared_ptr<Cache> sim_cache, std::shared_ptr<Cache> cache)
+      : cache_(cache),
+        key_only_cache_(sim_cache),
+        miss_times_(0),
+        hit_times_(0),
+        stats_(nullptr) {}
+
+  ~SimCacheImpl() override {}
+  void SetCapacity(size_t capacity) override { cache_->SetCapacity(capacity); }
+
+  void SetStrictCapacityLimit(bool strict_capacity_limit) override {
+    cache_->SetStrictCapacityLimit(strict_capacity_limit);
+  }
+
+  Status Insert(const Slice& key, void* value, size_t charge,
+                void (*deleter)(const Slice& key, void* value), Handle** handle,
+                Priority priority) override {
+    // The handle and value passed in are for real cache, so we pass nullptr
+    // to key_only_cache_ for both instead. Also, the deleter function pointer
+    // will be called by user to perform some external operation which should
+    // be applied only once. Thus key_only_cache accepts an empty function.
+    // *Lambda function without capture can be assgined to a function pointer
+    Handle* h = key_only_cache_->Lookup(key);
+    if (h == nullptr) {
+      key_only_cache_->Insert(key, nullptr, charge,
+                              [](const Slice& /*k*/, void* /*v*/) {}, nullptr,
+                              priority);
+    } else {
+      key_only_cache_->Release(h);
+    }
+
+    cache_activity_logger_.ReportAdd(key, charge);
+    if (!cache_) {
+      return Status::OK();
+    }
+    return cache_->Insert(key, value, charge, deleter, handle, priority);
+  }
+
+  Handle* Lookup(const Slice& key, Statistics* stats) override {
+    Handle* h = key_only_cache_->Lookup(key);
+    if (h != nullptr) {
+      key_only_cache_->Release(h);
+      inc_hit_counter();
+      RecordTick(stats, SIM_BLOCK_CACHE_HIT);
+    } else {
+      inc_miss_counter();
+      RecordTick(stats, SIM_BLOCK_CACHE_MISS);
+    }
+
+    cache_activity_logger_.ReportLookup(key);
+    if (!cache_) {
+      return nullptr;
+    }
+    return cache_->Lookup(key, stats);
+  }
+
+  bool Ref(Handle* handle) override { return cache_->Ref(handle); }
+
+  bool Release(Handle* handle, bool force_erase = false) override {
+    return cache_->Release(handle, force_erase);
+  }
+
+  void Erase(const Slice& key) override {
+    cache_->Erase(key);
+    key_only_cache_->Erase(key);
+  }
+
+  void* Value(Handle* handle) override { return cache_->Value(handle); }
+
+  uint64_t NewId() override { return cache_->NewId(); }
+
+  size_t GetCapacity() const override { return cache_->GetCapacity(); }
+
+  bool HasStrictCapacityLimit() const override {
+    return cache_->HasStrictCapacityLimit();
+  }
+
+  size_t GetUsage() const override { return cache_->GetUsage(); }
+
+  size_t GetUsage(Handle* handle) const override {
+    return cache_->GetUsage(handle);
+  }
+
+  size_t GetCharge(Handle* handle) const override {
+    return cache_->GetCharge(handle);
+  }
+
+  size_t GetPinnedUsage() const override { return cache_->GetPinnedUsage(); }
+
+  void DisownData() override {
+    cache_->DisownData();
+    key_only_cache_->DisownData();
+  }
+
+  void ApplyToAllCacheEntries(void (*callback)(void*, size_t),
+                              bool thread_safe) override {
+    // only apply to _cache since key_only_cache doesn't hold value
+    cache_->ApplyToAllCacheEntries(callback, thread_safe);
+  }
+
+  void EraseUnRefEntries() override {
+    cache_->EraseUnRefEntries();
+    key_only_cache_->EraseUnRefEntries();
+  }
+
+  size_t GetSimCapacity() const override {
+    return key_only_cache_->GetCapacity();
+  }
+  size_t GetSimUsage() const override { return key_only_cache_->GetUsage(); }
+  void SetSimCapacity(size_t capacity) override {
+    key_only_cache_->SetCapacity(capacity);
+  }
+
+  uint64_t get_miss_counter() const override {
+    return miss_times_.load(std::memory_order_relaxed);
+  }
+
+  uint64_t get_hit_counter() const override {
+    return hit_times_.load(std::memory_order_relaxed);
+  }
+
+  void reset_counter() override {
+    miss_times_.store(0, std::memory_order_relaxed);
+    hit_times_.store(0, std::memory_order_relaxed);
+    SetTickerCount(stats_, SIM_BLOCK_CACHE_HIT, 0);
+    SetTickerCount(stats_, SIM_BLOCK_CACHE_MISS, 0);
+  }
+
+  std::string ToString() const override {
+    std::string res;
+    res.append("SimCache MISSes: " + std::to_string(get_miss_counter()) + "\n");
+    res.append("SimCache HITs:    " + std::to_string(get_hit_counter()) + "\n");
+    char buff[350];
+    auto lookups = get_miss_counter() + get_hit_counter();
+    snprintf(buff, sizeof(buff), "SimCache HITRATE: %.2f%%\n",
+             (lookups == 0 ? 0 : get_hit_counter() * 100.0f / lookups));
+    res.append(buff);
+    return res;
+  }
+
+  std::string GetPrintableOptions() const override {
+    std::string ret;
+    ret.reserve(20000);
+    ret.append("    cache_options:\n");
+    ret.append(cache_->GetPrintableOptions());
+    ret.append("    sim_cache_options:\n");
+    ret.append(key_only_cache_->GetPrintableOptions());
+    return ret;
+  }
+
+  Status StartActivityLogging(const std::string& activity_log_file, Env* env,
+                              uint64_t max_logging_size = 0) override {
+    return cache_activity_logger_.StartLogging(activity_log_file, env,
+                                               max_logging_size);
+  }
+
+  void StopActivityLogging() override { cache_activity_logger_.StopLogging(); }
+
+  Status GetActivityLoggingStatus() override {
+    return cache_activity_logger_.bg_status();
+  }
+
+ private:
+  std::shared_ptr<Cache> cache_;
+  std::shared_ptr<Cache> key_only_cache_;
+  std::atomic<uint64_t> miss_times_;
+  std::atomic<uint64_t> hit_times_;
+  Statistics* stats_;
+  CacheActivityLogger cache_activity_logger_;
+
+  void inc_miss_counter() {
+    miss_times_.fetch_add(1, std::memory_order_relaxed);
+  }
+  void inc_hit_counter() { hit_times_.fetch_add(1, std::memory_order_relaxed); }
+};
+
+}  // end anonymous namespace
+
+// For instrumentation purpose, use NewSimCache instead
+std::shared_ptr<SimCache> NewSimCache(std::shared_ptr<Cache> cache,
+                                      size_t sim_capacity, int num_shard_bits) {
+  LRUCacheOptions co;
+  co.capacity = sim_capacity;
+  co.num_shard_bits = num_shard_bits;
+  co.metadata_charge_policy = kDontChargeCacheMetadata;
+  return NewSimCache(NewLRUCache(co), cache, num_shard_bits);
+}
+
+std::shared_ptr<SimCache> NewSimCache(std::shared_ptr<Cache> sim_cache,
+                                      std::shared_ptr<Cache> cache,
+                                      int num_shard_bits) {
+  if (num_shard_bits >= 20) {
+    return nullptr;  // the cache cannot be sharded into too many fine pieces
+  }
+  return std::make_shared<SimCacheImpl>(sim_cache, cache);
+}
+
+}  // namespace ROCKSDB_NAMESPACE