db_bench.cc

// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.

#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <vector>
#include "db/kv_store.hh"
#include "common/env.hh"
#include "common/status.hh"
#include "common/random.hh"
#include "common/testutil.hh"
#include "common/iterator.hh"

// Comma-separated list of operations to run in the specified order
//   Actual benchmarks:
//      fillseq       -- write N values in sequential key order in async mode
//      fillrandom    -- write N values in random key order in async mode
//      fillsync      -- write N/100 values in random key order in sync mode
//      readseq       -- read N times sequentially
//      readrandom    -- read N times in random order
//      readmissing   -- read N missing keys in random order
//      readhot       -- read N times in random order from 1% section of DB
//      seekrandom    -- N random seeks

static const char* FLAGS_benchmarks =
  "fillseq,"
  "fillrandom,"
  "readrandom,"
  "readseq,"
;

// Number of key/values to place in database
static int FLAGS_num = 1000000;

// Number of read operations to do.  If negative, do FLAGS_num reads.
static int FLAGS_reads = -1;

// Number of concurrent threads to run.
static int FLAGS_threads = 1;

// Size of each value
static int FLAGS_value_size = 100;

// Arrange to generate values that shrink to this fraction of
// their original size after compression
static double FLAGS_compression_ratio = 0.5;

// Use the db with the following name.
static const char* FLAGS_db = nullptr;

namespace {
Env* g_env = nullptr;

// Helper for quickly generating random data.
class RandomGenerator {
private:
  std::string data_;
  int pos_;

public:
  RandomGenerator() {
    // We use a limited amount of data over and over again and ensure
    // that it is larger than the compression window (32KB), and also
    // large enough to serve all typical value sizes we want to write.
    Random rnd(301);
    std::string piece;
    while (data_.size() < 1048576) {
      // Add a short fragment that is as compressible as specified
      // by FLAGS_compression_ratio.
      test::CompressibleString(&rnd, FLAGS_compression_ratio, 100, &piece);
      data_.append(piece);
    }
    pos_ = 0;
  }

  Slice Generate(size_t len) {
    if (pos_ + len > data_.size()) {
      pos_ = 0;
      assert(len < data_.size());
    }
    pos_ += len;
    return Slice(data_.data() + pos_ - len, len);
  }
};

#if defined(__linux)
static Slice TrimSpace(Slice s) {
  size_t start = 0;
  while (start < s.size() && isspace(s[start])) {
    start++;
  }
  size_t limit = s.size();
  while (limit > start && isspace(s[limit-1])) {
    limit--;
  }
  return Slice(s.data() + start, limit - start);
}
#endif

static void AppendWithSpace(std::string* str, Slice msg) {
  if (msg.empty()) return;
  if (!str->empty()) {
    str->push_back(' ');
  }
  str->append(msg.data(), msg.size());
}

class Stats {
private:
  double start_;
  double finish_;
  double seconds_;
  int done_;
  int next_report_;
  int64_t bytes_;
  double last_op_finish_;
  std::string message_;

public:
  Stats() { Start(); }

  void Start() {
    next_report_ = 100;
    last_op_finish_ = start_;
    done_ = 0;
    bytes_ = 0;
    seconds_ = 0;
    start_ = g_env->NowMicros();
    finish_ = start_;
    message_.clear();
  }

  void Merge(const Stats& other) {
    done_ += other.done_;
    bytes_ += other.bytes_;
    seconds_ += other.seconds_;
    if (other.start_ < start_) start_ = other.start_;
    if (other.finish_ > finish_) finish_ = other.finish_;

    // Just keep the messages from one thread
    if (message_.empty()) message_ = other.message_;
  }

  void Stop() {
    finish_ = g_env->NowMicros();
    seconds_ = (finish_ - start_) * 1e-6;
  }

  void AddMessage(Slice msg) {
    AppendWithSpace(&message_, msg);
  }

  void FinishedSingleOp() {
    done_++;
    if (done_ >= next_report_) {
      if      (next_report_ < 1000)   next_report_ += 100;
      else if (next_report_ < 5000)   next_report_ += 500;
      else if (next_report_ < 10000)  next_report_ += 1000;
      else if (next_report_ < 50000)  next_report_ += 5000;
      else if (next_report_ < 100000) next_report_ += 10000;
      else if (next_report_ < 500000) next_report_ += 50000;
      else                            next_report_ += 100000;
      fprintf(stderr, "... finished %d ops%30s\r", done_, "");
      fflush(stderr);
    }
  }

  void AddBytes(int64_t n) {
    bytes_ += n;
  }

  void Report(const Slice& name) {
    // Pretend at least one op was done in case we are running a benchmark
    // that does not call FinishedSingleOp().
    if (done_ < 1) done_ = 1;

    std::string extra;
    if (bytes_ > 0) {
      // Rate is computed on actual elapsed time, not the sum of per-thread
      // elapsed times.
      double elapsed = (finish_ - start_) * 1e-6;
      char rate[100];
      snprintf(rate, sizeof(rate), "%6.1f MB/s",
               (bytes_ / 1048576.0) / elapsed);
      extra = rate;
    }
    AppendWithSpace(&extra, message_);

    fprintf(stdout, "%-12s : %11.3f micros/op;%s%s\n",
            name.ToString().c_str(),
            seconds_ * 1e6 / done_,
            (extra.empty() ? "" : " "),
            extra.c_str());
    fflush(stdout);
  }
};

// State shared by all concurrent executions of the same benchmark.
struct SharedState {
  port::Mutex mu;
  port::CondVar cv GUARDED_BY(mu);
  int total GUARDED_BY(mu);

  // Each thread goes through the following states:
  //    (1) initializing
  //    (2) waiting for others to be initialized
  //    (3) running
  //    (4) done

  int num_initialized GUARDED_BY(mu);
  int num_done GUARDED_BY(mu);
  bool start GUARDED_BY(mu);

  SharedState(int total)
    : cv(&mu), total(total), num_initialized(0), num_done(0), start(false) { }
};

// Per-thread state for concurrent executions of the same benchmark.
struct ThreadState {
  int tid;             // 0..n-1 when running in n threads
  Random rand;         // Has different seeds for different threads
  Stats stats;
  SharedState* shared;

  ThreadState(int index)
    : tid(index),
      rand(1000 + index) {
  }
};

}  // namespace

class Benchmark {
private:
  KVStore* db_;
  int num_;
  int value_size_;
  int entries_per_batch_;
  int reads_;

  void PrintHeader() {
    const int kKeySize = 16;
    PrintEnvironment();
    fprintf(stdout, "Keys:       %d bytes each\n", kKeySize);
    fprintf(stdout, "Values:     %d bytes each (%d bytes after compression)\n",
            FLAGS_value_size,
            static_cast<int>(FLAGS_value_size * FLAGS_compression_ratio + 0.5));
    fprintf(stdout, "Entries:    %d\n", num_);
    fprintf(stdout, "RawSize:    %.1f MB (estimated)\n",
            ((static_cast<int64_t>(kKeySize + FLAGS_value_size) * num_)
             / 1048576.0));
    fprintf(stdout, "FileSize:   %.1f MB (estimated)\n",
            (((kKeySize + FLAGS_value_size * FLAGS_compression_ratio) * num_)
             / 1048576.0));
    PrintWarnings();
    fprintf(stdout, "------------------------------------------------\n");
  }

  void PrintWarnings() {
#if defined(__GNUC__) && !defined(__OPTIMIZE__)
    fprintf(stdout,
            "WARNING: Optimization is disabled: benchmarks unnecessarily slow\n"
    );
#endif
#ifndef NDEBUG
    fprintf(stdout,
            "WARNING: Assertions are enabled; benchmarks unnecessarily slow\n");
#endif
  }

  void PrintEnvironment() {

#if defined(__linux)
    time_t now = time(nullptr);
    fprintf(stderr, "Date:       %s", ctime(&now));  // ctime() adds newline

    FILE* cpuinfo = fopen("/proc/cpuinfo", "r");
    if (cpuinfo != nullptr) {
      char line[1000];
      int num_cpus = 0;
      std::string cpu_type;
      std::string cache_size;
      while (fgets(line, sizeof(line), cpuinfo) != nullptr) {
        const char* sep = strchr(line, ':');
        if (sep == nullptr) {
          continue;
        }
        Slice key = TrimSpace(Slice(line, sep - 1 - line));
        Slice val = TrimSpace(Slice(sep + 1));
        if (key == "model name") {
          ++num_cpus;
          cpu_type = val.ToString();
        } else if (key == "cache size") {
          cache_size = val.ToString();
        }
      }
      fclose(cpuinfo);
      fprintf(stderr, "CPU:        %d * %s\n", num_cpus, cpu_type.c_str());
      fprintf(stderr, "CPUCache:   %s\n", cache_size.c_str());
    }
#endif
  }

public:
  Benchmark()
    : db_(nullptr),
      num_(FLAGS_num),
      value_size_(FLAGS_value_size),
      entries_per_batch_(1),
      reads_(FLAGS_reads < 0 ? FLAGS_num : FLAGS_reads) { }

  ~Benchmark() {
    delete db_;
  }

  void Run() {
    PrintHeader();
    db_ = new KVStore();

    const char* benchmarks = FLAGS_benchmarks;
    while (benchmarks != nullptr) {
      const char* sep = strchr(benchmarks, ',');
      Slice name;
      if (sep == nullptr) {
        name = benchmarks;
        benchmarks = nullptr;
      } else {
        name = Slice(benchmarks, sep - benchmarks);
        benchmarks = sep + 1;
      }

      // Reset parameters that may be overridden below
      num_ = FLAGS_num;
      reads_ = (FLAGS_reads < 0 ? FLAGS_num : FLAGS_reads);
      value_size_ = FLAGS_value_size;
      entries_per_batch_ = 1;

      void (Benchmark::*method)(ThreadState*) = nullptr;
      int num_threads = FLAGS_threads;

      if (name == Slice("fillseq")) {
        method = &Benchmark::WriteSeq;
      } else if (name == Slice("fillrandom")) {
        method = &Benchmark::WriteRandom;
      } else if (name == Slice("overwrite")) {
        method = &Benchmark::WriteRandom;
      } else if (name == Slice("fillsync")) {
        num_ /= 1000;
        method = &Benchmark::WriteRandom;
      } else if (name == Slice("readseq")) {
        method = &Benchmark::ReadSequential;
      } else if (name == Slice("readrandom")) {
        method = &Benchmark::ReadRandom;
      } else if (name == Slice("seekrandom")) {
        method = &Benchmark::SeekRandom;
      } else {
        if (name != Slice()) {  // No error message for empty name
          fprintf(stderr, "unknown benchmark '%s'\n", name.ToString().c_str());
        }
      }

      if (method != nullptr) {
        RunBenchmark(num_threads, name, method);
      }
    }
  }

private:
  struct ThreadArg {
    Benchmark* bm;
    SharedState* shared;
    ThreadState* thread;
    void (Benchmark::*method)(ThreadState*);
  };

  static void ThreadBody(void* v) {
    ThreadArg* arg = reinterpret_cast<ThreadArg*>(v);
    SharedState* shared = arg->shared;
    ThreadState* thread = arg->thread;
    {
      port::MutexLock l(&shared->mu);
      shared->num_initialized++;
      if (shared->num_initialized >= shared->total) {
        shared->cv.SignalAll();
      }
      while (!shared->start) {
        shared->cv.Wait();
      }
    }

    thread->stats.Start();
    (arg->bm->*(arg->method))(thread);
    thread->stats.Stop();

    {
      port::MutexLock l(&shared->mu);
      shared->num_done++;
      if (shared->num_done >= shared->total) {
        shared->cv.SignalAll();
      }
    }
  }

  void RunBenchmark(int n, Slice name,
                    void (Benchmark::*method)(ThreadState*)) {
    SharedState shared(n);

    ThreadArg* arg = new ThreadArg[n];
    for (int i = 0; i < n; i++) {
      arg[i].bm = this;
      arg[i].method = method;
      arg[i].shared = &shared;
      arg[i].thread = new ThreadState(i);
      arg[i].thread->shared = &shared;
      g_env->StartThread(ThreadBody, &arg[i]);
    }

    shared.mu.Lock();
    while (shared.num_initialized < n) {
      shared.cv.Wait();
    }

    shared.start = true;
    shared.cv.SignalAll();
    while (shared.num_done < n) {
      shared.cv.Wait();
    }
    shared.mu.Unlock();

    for (int i = 1; i < n; i++) {
      arg[0].thread->stats.Merge(arg[i].thread->stats);
    }
    arg[0].thread->stats.Report(name);

    for (int i = 0; i < n; i++) {
      delete arg[i].thread;
    }
    delete[] arg;
  }

  void WriteSeq(ThreadState* thread) {
    DoWrite(thread, true);
  }

  void WriteRandom(ThreadState* thread) {
    DoWrite(thread, false);
  }

  void DoWrite(ThreadState* thread, bool seq) {
    if (num_ != FLAGS_num) {
      char msg[100];
      snprintf(msg, sizeof(msg), "(%d ops)", num_);
      thread->stats.AddMessage(msg);
    }

    RandomGenerator gen;
    Status s;
    int64_t bytes = 0;
    for (int i = 0; i < num_; i += entries_per_batch_) {
      for (int j = 0; j < entries_per_batch_; j++) {
        const int k = seq ? i+j : (thread->rand.Next() % FLAGS_num);
        char key[100];
        snprintf(key, sizeof(key), "%016d", k);
        s = db_->Put(key, gen.Generate(value_size_));
        bytes += value_size_ + strlen(key);
        thread->stats.FinishedSingleOp();
      }
      if (!s.ok()) {
        fprintf(stderr, "put error: %s\n", s.ToString().c_str());
        exit(1);
      }
    }
    thread->stats.AddBytes(bytes);
  }

  void ReadSequential(ThreadState* thread) {
    Iterator* iter = db_->NewIterator();
    int i = 0;
    int64_t bytes = 0;
    for (iter->SeekToFirst(); i < reads_ && iter->Valid(); iter->Next()) {
      bytes += iter->key().size() + iter->value().size();
      thread->stats.FinishedSingleOp();
      ++i;
    }
    delete iter;
    thread->stats.AddBytes(bytes);
  }

  void ReadRandom(ThreadState* thread) {
    Slice value;
    int found = 0;
    for (int i = 0; i < reads_; i++) {
      char key[100];
      const int k = thread->rand.Next() % FLAGS_num;
      snprintf(key, sizeof(key), "%016d", k);
      if (db_->Get(key, &value).ok()) {
        found++;
      }
      thread->stats.FinishedSingleOp();
    }
    char msg[100];
    snprintf(msg, sizeof(msg), "(%d of %d found)", found, num_);
    thread->stats.AddMessage(msg);
  }

  void SeekRandom(ThreadState* thread) {
    int found = 0;
    for (int i = 0; i < reads_; i++) {
      Iterator* iter = db_->NewIterator();
      char key[100];
      const int k = thread->rand.Next() % FLAGS_num;
      snprintf(key, sizeof(key), "%016d", k);
      iter->Seek(key);
      if (iter->Valid() && iter->key() == key) found++;
      delete iter;
      thread->stats.FinishedSingleOp();
    }
    char msg[100];
    snprintf(msg, sizeof(msg), "(%d of %d found)", found, num_);
    thread->stats.AddMessage(msg);
  }
};

int main(int argc, char** argv) {
  std::string default_db_path;

  for (int i = 1; i < argc; i++) {
    double d;
    int n;
    char junk;
    if (Slice(argv[i]).starts_with("--benchmarks=")) {
      FLAGS_benchmarks = argv[i] + strlen("--benchmarks=");
    } else if (sscanf(argv[i], "--num=%d%c", &n, &junk) == 1) {
      FLAGS_num = n;
    } else if (sscanf(argv[i], "--reads=%d%c", &n, &junk) == 1) {
      FLAGS_reads = n;
    } else if (sscanf(argv[i], "--value_size=%d%c", &n, &junk) == 1) {
      FLAGS_value_size = n;
    } else if (strncmp(argv[i], "--db=", 5) == 0) {
      FLAGS_db = argv[i] + 5;
    } else {
      fprintf(stderr, "Invalid flag '%s'\n", argv[i]);
      exit(1);
    }
  }

  g_env = Env::Default();

  // Choose a location for the test database if none given with --db=<path>
  if (FLAGS_db == nullptr) {
    g_env->GetTestDirectory(&default_db_path);
    default_db_path += "/dbbench";
    FLAGS_db = default_db_path.c_str();
  }

  Benchmark benchmark;
  benchmark.Run();
  return 0;
}