diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..0c6eb29
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+*.[oais]
+/main
+*~
+*.ii
+*.bc
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..0738284
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,19 @@
+# -fsanitize=undefined
+CXXFLAGS += -std=c++11 -O3 -Wall -Wextra -I/usr/include/rados -I/usr/include/jsoncpp
+#-Wa,-adhln -g
+LDFLAGS += -pthread -lrados -ljsoncpp -lstdc++
+
+#CC=clang-6.0
+
+
+main: main.o
+	$(CC) $^ -o $@ $(LDFLAGS)
+
+.cpp.o:
+	$(CC) $(CPPFLAGS) $(CXXFLAGS) -c $< -o $@
+
+indent: main.cpp
+	clang-format-6.0 -i main.cpp
+
+builddep:
+	sudo apt install -y --no-install-recommends libjsoncpp-dev
diff --git a/main.cpp b/main.cpp
new file mode 100644
index 0000000..557c2df
--- /dev/null
+++ b/main.cpp
@@ -0,0 +1,418 @@
+#include <chrono>
+#include <iostream>
+#include <json/json.h>
+#include <librados.hpp>
+#include <map>
+#include <set>
+#include <string>
+#include <thread>
+#include <vector>
+
+using namespace librados;
+using namespace std;
+using namespace chrono;
+
+template <class T> static double dur2sec(const T &dur) {
+  return duration_cast<duration<double>>(dur).count();
+}
+
+template <class T> static double dur2msec(const T &dur) {
+  return duration_cast<duration<double, milli>>(dur).count();
+}
+
+template <class T>
+static void print_breakdown(const vector<T> &summary, size_t thread_count) {
+
+  T totaltime(0);
+
+  map<size_t, size_t> dur2count;
+  map<size_t, T> dur2totaltime;
+  static const size_t usecs[] = {
+      100,   200,   300,   400,   500,   600,   700,   800,    900,       1000,
+      2000,  3000,  4000,  5000,  6000,  7000,  8000,  9000,   10000,     20000,
+      30000, 40000, 50000, 60000, 70000, 80000, 90000, 100000, 1000000000};
+
+  for (const auto &m : usecs) {
+    dur2count[m] = 0;
+    dur2totaltime[m] = T(0);
+  }
+
+  T mindur(minutes(42));
+  T maxdur(0);
+  for (const auto &res : summary) {
+    totaltime += res;
+    if (res > maxdur)
+      maxdur = res;
+    if (res < mindur)
+      mindur = res;
+    for (const auto &m : usecs) {
+      if (res <= microseconds(m)) {
+        dur2count.at(m)++;
+        dur2totaltime.at(m) += res;
+        break;
+      }
+    }
+  }
+
+  cout << "min delay " << dur2msec(mindur) << " msec." << endl;
+  cout << "max delay " << dur2msec(maxdur) << " msec." << endl;
+
+  // skip first counters equal zero
+  auto b = dur2count.begin();
+  while (b != dur2count.end() && !b->second)
+    b++;
+
+  // skip last counters equal zero
+  auto e = dur2count.end();
+  if (e != b) {
+    e--;
+    while (e != b && !e->second)
+      e--;
+    e++;
+  }
+
+  size_t maxcount = 0;
+  for (auto p = b; p != e; p++) {
+    const auto &usecgroup = p->first;
+    const auto &count = p->second;
+    //      const auto &timespent = dur2totaltime.at(usecgroup);
+
+    if (count > maxcount)
+      maxcount = count;
+
+    auto bar = std::string(count * 70 / summary.size(), '#');
+    if (usecgroup == 1000000000)
+      cout << ">   100";
+    else
+      cout << "<=" << setw(5) << usecgroup / 1000.0;
+    cout << " ms: " << setw(3) << count * 100 / summary.size() << "% " << bar
+         << " cnt=" << count;
+    //     cout << " (" << (count * thread_count) / dur2sec(timespent)
+    //           << " IOPS)";
+    cout << endl;
+  }
+
+  size_t sum = 0;
+  T sumtime(0);
+  for (auto p = b; p != e; p++) {
+    const auto &usecgroup = p->first;
+    const auto &count = p->second;
+    if (count > maxcount / 100.0) {
+      sum += count;
+      sumtime += dur2totaltime.at(usecgroup);
+    }
+  }
+
+  cout << "ops: " << (summary.size() * thread_count) / dur2sec(totaltime)
+       << endl;
+
+  cout << "ops (count > 0.01 of max): "
+       << (sum * thread_count) / dur2sec(sumtime) << endl;
+
+  if (thread_count > 1)
+    cout << "ops per thread: " << summary.size() / dur2sec(totaltime) << endl;
+}
+
+// Called in a thread.
+static void _do_bench(unsigned int secs, const string &obj_name, IoCtx &ioctx,
+                      vector<steady_clock::duration> *ops) {
+  auto b = steady_clock::now();
+  const auto stop = b + seconds(secs);
+
+  //      cout<<"tt" <<ops<<endl;
+
+  bufferlist bar1;
+  bufferlist bar2;
+  // interleave buffers
+  bar1.append("q");
+  bar2.append("w");
+
+  // TODO: wait for SIGINT (!)
+  try {
+    while (b <= stop) {
+      if (ioctx.write_full(obj_name, ops->size() % 2 ? bar1 : bar2) < 0)
+        throw "Write error";
+      const auto b2 = steady_clock::now();
+      ops->push_back(b2 - b);
+      b = b2;
+    }
+  } catch (...) {
+    ioctx.remove(obj_name); // ignore errors.
+    throw;
+  }
+  ioctx.remove(obj_name); // ignore errors.
+}
+
+static void do_bench(unsigned int secs, const vector<string> &names,
+                     IoCtx &ioctx) {
+
+  vector<steady_clock::duration> summary;
+
+  if (names.size() > 1) {
+    vector<thread> threads;
+    vector<vector<steady_clock::duration> *> listofopts;
+
+    for (const auto &name : names) {
+      auto results = new vector<steady_clock::duration>;
+      listofopts.push_back(results);
+      threads.push_back(thread(_do_bench, secs, name, ref(ioctx), results));
+    }
+
+    for (auto &th : threads)
+      th.join();
+
+    // just an optimisation :)
+    size_t qwe = 0;
+    for (const auto &res : listofopts)
+      qwe += res->size();
+    summary.reserve(qwe);
+
+    for (const auto &res : listofopts) {
+      summary.insert(summary.end(), res->begin(), res->end());
+      delete res;
+    }
+  } else {
+    _do_bench(secs, names.at(0), ioctx, &summary);
+  }
+  print_breakdown(summary, names.size());
+}
+
+class RadosUtils {
+public:
+  RadosUtils(Rados *rados_)
+      : rados(rados_), json_reader(Json::Features::strictMode()) {}
+
+  unsigned int get_obj_acting_primary(const string &name, const string &pool) {
+
+    Json::Value cmd(Json::objectValue);
+    cmd["prefix"] = "osd map";
+    cmd["object"] = name;
+    cmd["pool"] = pool;
+
+    auto &&location = do_mon_command(cmd);
+
+    const auto &acting_primary = location["acting_primary"];
+    if (!acting_primary.isNumeric())
+      throw "Failed to get acting_primary";
+
+    return acting_primary.asUInt();
+  }
+
+  map<string, string> get_osd_location(unsigned int osd) {
+    Json::Value cmd(Json::objectValue);
+    cmd["prefix"] = "osd find";
+    cmd["id"] = osd;
+
+    auto &&location = do_mon_command(cmd);
+    const auto &crush = location["crush_location"];
+
+    map<string, string> result;
+
+    for (auto &&it = crush.begin(); it != crush.end(); ++it) {
+      result[it.name()] = it->asString();
+    }
+
+    result["osd"] = "osd." + to_string(osd);
+
+    return result;
+  }
+
+  set<unsigned int> get_osds(const string &pool) {
+    Json::Value cmd(Json::objectValue);
+    cmd["prefix"] = "pg ls-by-pool";
+    cmd["poolstr"] = pool;
+
+    const auto &&pgs = do_mon_command(cmd);
+
+    set<unsigned int> osds;
+
+    // TODO:
+    // auto const & x: container
+    // https://stackoverflow.com/questions/27307373/c-how-to-create-iterator-over-one-field-of-a-struct-vector
+    for (const auto &pg : pgs) {
+      const auto &primary = pg["acting_primary"];
+      if (!primary.isNumeric())
+        throw "Failed to get acting_primary";
+      osds.insert(primary.asUInt());
+    }
+
+    return osds;
+  }
+
+  unsigned int get_pool_size(const string &pool) {
+    Json::Value cmd(Json::objectValue);
+    cmd["prefix"] = "osd pool get";
+    cmd["pool"] = pool;
+    cmd["var"] = "size";
+
+    const auto &&v = do_mon_command(cmd);
+
+    return v["size"].asUInt();
+  }
+
+private:
+  Json::Value do_mon_command(Json::Value &cmd) {
+    int err;
+    bufferlist outbl;
+    string outs;
+    cmd["format"] = "json";
+    bufferlist inbl;
+    if ((err = rados->mon_command(json_writer.write(cmd), inbl, &outbl,
+                                  &outs)) < 0) {
+      cerr << "mon_command error: " << outs << endl;
+      throw "mon_command error";
+    }
+
+    Json::Value root;
+    if (!json_reader.parse(outbl.to_str(), root))
+      throw "JSON parse error";
+
+    return root;
+  }
+
+  Rados *rados;
+  Json::Reader json_reader;
+  Json::FastWriter json_writer;
+};
+
+static void _main(int argc, const char *argv[]) {
+  struct {
+    string pool;
+    string mode;
+    string specific_bench_item;
+    unsigned int threads;
+    unsigned int secs;
+  } settings;
+
+  Rados rados;
+
+  int err;
+  if ((err = rados.init("admin")) < 0) {
+    cerr << "Failed to init: " << strerror(-err) << endl;
+    throw "Failed to init";
+  }
+
+  if ((err = rados.conf_read_file("/etc/ceph/ceph.conf")) < 0) {
+    cerr << "Failed to read conf file: " << strerror(-err) << endl;
+    throw "Failed to read conf file";
+  }
+
+  if ((err = rados.conf_parse_argv(argc, argv)) < 0) {
+    cerr << "Failed to parse argv: " << strerror(-err) << endl;
+    throw "Failed to parse argv";
+  }
+
+  switch (argc) {
+  case 3:
+    settings.pool = argv[1];
+    settings.mode = argv[2];
+    break;
+  case 4:
+    settings.pool = argv[1];
+    settings.mode = argv[2];
+    settings.specific_bench_item = argv[3];
+    break;
+  default:
+    cerr << "Usage: " << argv[0]
+         << " [poolname] [mode=host|osd] <specific item name to test>" << endl;
+    throw "Wrong cmdline";
+  }
+
+  settings.secs = 10;
+  settings.threads = 1;
+
+  if ((err = rados.connect()) < 0) {
+    cerr << "Failed to connect: " << strerror(-err) << endl;
+    throw "Failed to connect";
+  }
+
+  // https://tracker.ceph.com/issues/24114
+  this_thread::sleep_for(milliseconds(100));
+
+  auto rados_utils = RadosUtils(&rados);
+
+  if (rados_utils.get_pool_size(settings.pool) != 1)
+    throw "It's required to have pool size 1";
+
+  map<unsigned int, map<string, string>> osd2location;
+
+  set<string> bench_items; // node1, node2 ||| osd.1, osd.2, osd.3
+
+  for (const auto &osd : rados_utils.get_osds(settings.pool)) {
+    const auto &location = rados_utils.get_osd_location(osd);
+
+    // TODO: do not fill this map if specific_bench_item specified
+    osd2location[osd] = location;
+
+    const auto &qwe = location.at(settings.mode);
+    if (settings.specific_bench_item.empty() ||
+        qwe == settings.specific_bench_item) {
+      bench_items.insert(qwe);
+    }
+  }
+
+  // benchitem -> [name1, name2] ||| i.e. "osd.2" => ["obj1", "obj2"]
+  map<string, vector<string>> name2location;
+  unsigned int cnt = 0;
+
+  // for each bench_item find thread_count names.
+  // store every name in name2location = [bench_item, names, description]
+  const string prefix = "bench_";
+  while (bench_items.size()) {
+    string name = prefix + to_string(++cnt);
+
+    unsigned int osd = rados_utils.get_obj_acting_primary(name, settings.pool);
+
+    const auto &location = osd2location.at(osd);
+    const auto &bench_item = location.at(settings.mode);
+    if (!bench_items.count(bench_item))
+      continue;
+
+    auto &names = name2location[bench_item];
+    if (names.size() == settings.threads) {
+      bench_items.erase(bench_item);
+      continue;
+    }
+
+    names.push_back(name);
+
+    cout << name << " - " << bench_item << endl;
+  }
+
+  IoCtx ioctx;
+  // TODO: cleanup
+  /*
+   * NOTE: be sure to call watch_flush() prior to destroying any IoCtx
+   * that is used for watch events to ensure that racing callbacks
+   * have completed.
+   */
+
+  if (rados.ioctx_create(settings.pool.c_str(), ioctx) < 0)
+    throw "Failed to create ioctx";
+
+  for (const auto &p : name2location) {
+    const auto &bench_item = p.first;
+    const auto &obj_names = p.second;
+    cout << "Benching " << settings.mode << " " << bench_item << endl;
+    do_bench(settings.secs, obj_names, ioctx);
+  }
+}
+
+int main(int argc, const char *argv[]) {
+  /*
+   * IoCtx p;
+   * rados.ioctx_create("my_pool", p);
+   * p->stat(&stats);
+
+
+   */
+  try {
+    _main(argc, argv);
+  } catch (const char *msg) {
+    cerr << "Unhandled exception: " << msg << endl;
+    return 1;
+  }
+
+  cout << "Exiting successfully." << endl;
+  return 0;
+}
diff --git a/main.py b/main.py
index 137bc3a..b562987 100755
--- a/main.py
+++ b/main.py
@@ -301,10 +301,11 @@ def main():
 
                 iops = ops / elapsed
                 log.info(
-                    '%s %r: %2.2f IOPS, minlat=%.4f ms, maxlat=%.4f ms. %s.',
+                    '%s %r: %2.2f IOPS (%2.2f ops), minlat=%.4f ms, maxlat=%.4f ms. %s.',
                     mode,
                     bench_item,
                     iops,
+                    ops,
                     latencies[0] * 1000,
                     latencies[-1] * 1000,
                     description,