Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1067 insertions, 0 deletions

diff --git a/src/test/perf_local.cc b/src/test/perf_local.cc
new file mode 100644
index 000000000..ecd7dc792
--- /dev/null
+++ b/src/test/perf_local.cc
@@ -0,0 +1,1067 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/* Copyright (c) 2015 Haomai Wang <haomaiwang@gmail.com>
+ * Copyright (c) 2011-2014 Stanford University
+ * Copyright (c) 2011 Facebook
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR(S) DISCLAIM ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL AUTHORS BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+// This program contains a collection of low-level performance measurements
+// for Ceph, which can be run either individually or altogether.  These
+// tests measure performance in a single stand-alone process, not in a cluster
+// with multiple servers.  Invoke the program like this:
+//
+//     Perf test1 test2 ...
+//
+// test1 and test2 are the names of individual performance measurements to
+// run.  If no test names are provided then all of the performance tests
+// are run.
+//
+// To add a new test:
+// * Write a function that implements the test.  Use existing test functions
+//   as a guideline, and be sure to generate output in the same form as
+//   other tests.
+// * Create a new entry for the test in the #tests table.
+#include <vector>
+#include <sched.h>
+
+#include "acconfig.h"
+#ifdef HAVE_SSE
+#include <xmmintrin.h>
+#endif
+
+#include "include/buffer.h"
+#include "include/encoding.h"
+#include "include/ceph_hash.h"
+#include "include/spinlock.h"
+#include "common/ceph_argparse.h"
+#include "common/Cycles.h"
+#include "common/Cond.h"
+#include "common/ceph_mutex.h"
+#include "common/Thread.h"
+#include "common/Timer.h"
+#include "msg/async/Event.h"
+#include "global/global_init.h"
+
+#include "test/perf_helper.h"
+
+#include <atomic>
+
+using namespace ceph;
+
+/**
+ * Ask the operating system to pin the current thread to a given CPU.
+ *
+ * \param cpu
+ *      Indicates the desired CPU and hyperthread; low order 2 bits
+ *      specify CPU, next bit specifies hyperthread.
+ */
+void bind_thread_to_cpu(int cpu)
+{
+#ifdef HAVE_SCHED
+  cpu_set_t set;
+  CPU_ZERO(&set);
+  CPU_SET(cpu, &set);
+  sched_setaffinity(0, sizeof(set), &set);
+#endif
+}
+
+/*
+ * This function just discards its argument. It's used to make it
+ * appear that data is used,  so that the compiler won't optimize
+ * away the code we're trying to measure.
+ *
+ * \param value
+ *      Pointer to arbitrary value; it's discarded.
+ */
+void discard(void* value) {
+  int x = *reinterpret_cast<int*>(value);
+  if (x == 0x43924776) {
+    printf("Value was 0x%x\n", x);
+  }
+}
+
+//----------------------------------------------------------------------
+// Test functions start here
+//----------------------------------------------------------------------
+
+// Measure the cost of atomic compare-and-swap
+double atomic_int_cmp()
+{
+  int count = 1000000;
+  std::atomic<unsigned> value = { 11 };
+  unsigned int test = 11;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    value.compare_exchange_strong(test, test+2);
+    test += 2;
+  }
+  uint64_t stop = Cycles::rdtsc();
+  // printf("Final value: %d\n", value.load());
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of incrementing an atomic
+double atomic_int_inc()
+{
+  int count = 1000000;
+  std::atomic<int64_t> value = { 11 };
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    value++;
+  }
+  uint64_t stop = Cycles::rdtsc();
+  // printf("Final value: %d\n", value.load());
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of reading an atomic
+double atomic_int_read()
+{
+  int count = 1000000;
+  std::atomic<int64_t> value = { 11 };
+  int total = 0;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    total += value;
+  }
+  uint64_t stop = Cycles::rdtsc();
+  // printf("Total: %d\n", total);
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of storing a new value in an atomic
+double atomic_int_set()
+{
+  int count = 1000000;
+  std::atomic<int64_t> value = { 11 };
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    value = 88;
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of acquiring and releasing a mutex in the
+// fast case where the mutex is free.
+double mutex_nonblock()
+{
+  int count = 1000000;
+  ceph::mutex m = ceph::make_mutex("mutex_nonblock::m");
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    m.lock();
+    m.unlock();
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of allocating and deallocating a buffer, plus
+// appending (logically) one ptr.
+double buffer_basic()
+{
+  int count = 1000000;
+  uint64_t start = Cycles::rdtsc();
+  bufferptr ptr("abcdefg", 7);
+  for (int i = 0; i < count; i++) {
+    bufferlist b;
+    b.append(ptr, 0, 5);
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+struct DummyBlock {
+  int a = 1, b = 2, c = 3, d = 4;
+  void encode(bufferlist &bl) const {
+    ENCODE_START(1, 1, bl);
+    encode(a, bl);
+    encode(b, bl);
+    encode(c, bl);
+    encode(d, bl);
+    ENCODE_FINISH(bl);
+  }
+  void decode(bufferlist::const_iterator &bl) {
+    DECODE_START(1, bl);
+    decode(a, bl);
+    decode(b, bl);
+    decode(c, bl);
+    decode(d, bl);
+    DECODE_FINISH(bl);
+  }
+};
+WRITE_CLASS_ENCODER(DummyBlock)
+
+// Measure the cost of encoding and decoding a buffer, plus
+// allocating space for one chunk.
+double buffer_encode_decode()
+{
+  int count = 1000000;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    bufferlist b;
+    DummyBlock dummy_block;
+    encode(dummy_block, b);
+    auto iter = b.cbegin();
+    decode(dummy_block, iter);
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of allocating and deallocating a buffer, plus
+// copying in a small block.
+double buffer_basic_copy()
+{
+  int count = 1000000;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    bufferlist b;
+    b.append("abcdefg", 6);
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of making a copy of parts of two ptrs.
+double buffer_copy()
+{
+  int count = 1000000;
+  bufferlist b;
+  b.append("abcde", 5);
+  b.append("01234", 5);
+  char copy[10];
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    b.cbegin(2).copy(6, copy);
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of allocating new space by extending the
+// bufferlist
+double buffer_encode()
+{
+  int count = 100000;
+  uint64_t total = 0;
+  for (int i = 0; i < count; i++) {
+    bufferlist b;
+    DummyBlock dummy_block;
+    encode(dummy_block, b);
+    uint64_t start = Cycles::rdtsc();
+    encode(dummy_block, b);
+    encode(dummy_block, b);
+    encode(dummy_block, b);
+    encode(dummy_block, b);
+    encode(dummy_block, b);
+    encode(dummy_block, b);
+    encode(dummy_block, b);
+    encode(dummy_block, b);
+    encode(dummy_block, b);
+    encode(dummy_block, b);
+    total += Cycles::rdtsc() - start;
+  }
+  return Cycles::to_seconds(total)/(count*10);
+}
+
+// Measure the cost of creating an iterator and iterating over 10
+// chunks in a buffer.
+double buffer_iterator()
+{
+  bufferlist b;
+  const char s[] = "abcdefghijklmnopqrstuvwxyz";
+  bufferptr ptr(s, sizeof(s));
+  for (int i = 0; i < 5; i++) {
+    b.append(ptr, i, 5);
+  }
+  int count = 100000;
+  int sum = 0;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    auto it = b.cbegin();
+    while (!it.end()) {
+      sum += (static_cast<const char*>(it.get_current_ptr().c_str()))[it.get_remaining()-1];
+      ++it;
+    }
+  }
+  uint64_t stop = Cycles::rdtsc();
+  discard(&sum);
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Implements the CondPingPong test.
+class CondPingPong {
+  ceph::mutex mutex = ceph::make_mutex("CondPingPong::mutex");
+  ceph::condition_variable cond;
+  int prod = 0;
+  int cons = 0;
+  const int count = 10000;
+
+  class Consumer : public Thread {
+    CondPingPong *p;
+   public:
+    explicit Consumer(CondPingPong *p): p(p) {}
+    void* entry() override {
+      p->consume();
+      return 0;
+    }
+  } consumer;
+
+ public:
+  CondPingPong(): consumer(this) {}
+
+  double run() {
+    consumer.create("consumer");
+    uint64_t start = Cycles::rdtsc();
+    produce();
+    uint64_t stop = Cycles::rdtsc();
+    consumer.join();
+    return Cycles::to_seconds(stop - start)/count;
+  }
+
+  void produce() {
+    std::unique_lock l{mutex};
+    while (cons < count) {
+      cond.wait(l, [this] { return cons >= prod; });
+      ++prod;
+      cond.notify_all();
+    }
+  }
+
+  void consume() {
+    std::unique_lock l{mutex};
+    while (cons < count) {
+      cond.wait(l, [this] { return cons != prod; });
+      ++cons;
+      cond.notify_all();
+    }
+  }
+};
+
+// Measure the cost of coordinating between threads using a condition variable.
+double cond_ping_pong()
+{
+  return CondPingPong().run();
+}
+
+// Measure the cost of a 32-bit divide. Divides don't take a constant
+// number of cycles. Values were chosen here semi-randomly to depict a
+// fairly expensive scenario. Someone with fancy ALU knowledge could
+// probably pick worse values.
+double div32()
+{
+#if defined(__i386__) || defined(__x86_64__)
+  int count = 1000000;
+  uint64_t start = Cycles::rdtsc();
+  // NB: Expect an x86 processor exception is there's overflow.
+  uint32_t numeratorHi = 0xa5a5a5a5U;
+  uint32_t numeratorLo = 0x55aa55aaU;
+  uint32_t divisor = 0xaa55aa55U;
+  uint32_t quotient;
+  uint32_t remainder;
+  for (int i = 0; i < count; i++) {
+    __asm__ __volatile__("div %4" :
+                         "=a"(quotient), "=d"(remainder) :
+                         "a"(numeratorLo), "d"(numeratorHi), "r"(divisor) :
+                         "cc");
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+#elif defined(__aarch64__)
+  int count = 1000000;
+  uint64_t start = Cycles::rdtsc();
+  uint64_t numerator = 0xa5a5a5a555aa55aaUL;
+  uint32_t divisor = 0xaa55aa55U;
+  uint32_t result;
+  for (int i = 0; i < count; i++) {
+    asm volatile("udiv %0, %1, %2" : "=r"(result) :
+                  "r"(numerator), "r"(divisor));
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+#else
+  return -1;
+#endif
+}
+
+// Measure the cost of a 64-bit divide. Divides don't take a constant
+// number of cycles. Values were chosen here semi-randomly to depict a
+// fairly expensive scenario. Someone with fancy ALU knowledge could
+// probably pick worse values.
+double div64()
+{
+#if defined(__x86_64__) || defined(__amd64__)
+  int count = 1000000;
+  // NB: Expect an x86 processor exception is there's overflow.
+  uint64_t start = Cycles::rdtsc();
+  uint64_t numeratorHi = 0x5a5a5a5a5a5UL;
+  uint64_t numeratorLo = 0x55aa55aa55aa55aaUL;
+  uint64_t divisor = 0xaa55aa55aa55aa55UL;
+  uint64_t quotient;
+  uint64_t remainder;
+  for (int i = 0; i < count; i++) {
+    __asm__ __volatile__("divq %4" :
+                         "=a"(quotient), "=d"(remainder) :
+                         "a"(numeratorLo), "d"(numeratorHi), "r"(divisor) :
+                         "cc");
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+#else
+  return -1;
+#endif
+}
+
+// Measure the cost of calling a non-inlined function.
+double function_call()
+{
+  int count = 1000000;
+  uint64_t x = 0;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    x = PerfHelper::plus_one(x);
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the minimum cost of EventCenter::process_events, when there are no
+// Pollers and no Timers.
+double eventcenter_poll()
+{
+  int count = 1000000;
+  EventCenter center(g_ceph_context);
+  center.init(1000, 0, "posix");
+  center.set_owner();
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    center.process_events(0);
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+class CenterWorker : public Thread {
+  CephContext *cct;
+  bool done;
+
+ public:
+  EventCenter center;
+  explicit CenterWorker(CephContext *c): cct(c), done(false), center(c) {
+    center.init(100, 0, "posix");
+  }
+  void stop() {
+    done = true;
+    center.wakeup();
+  }
+  void* entry() override {
+    center.set_owner();
+    bind_thread_to_cpu(2);
+    while (!done)
+      center.process_events(1000);
+    return 0;
+  }
+};
+
+class CountEvent: public EventCallback {
+  std::atomic<int64_t> *count;
+
+ public:
+  explicit CountEvent(std::atomic<int64_t> *atomic): count(atomic) {}
+  void do_request(uint64_t id) override {
+    (*count)--;
+  }
+};
+
+double eventcenter_dispatch()
+{
+  int count = 100000;
+
+  CenterWorker worker(g_ceph_context);
+  std::atomic<int64_t> flag = { 1 };
+  worker.create("evt_center_disp");
+  EventCallbackRef count_event(new CountEvent(&flag));
+
+  worker.center.dispatch_event_external(count_event);
+  // Start a new thread and wait for it to ready.
+  while (flag)
+    usleep(100);
+
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    flag = 1;
+    worker.center.dispatch_event_external(count_event);
+    while (flag)
+      ;
+  }
+  uint64_t stop = Cycles::rdtsc();
+  worker.stop();
+  worker.join();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of copying a given number of bytes with memcpy.
+double memcpy_shared(size_t size)
+{
+  int count = 1000000;
+  char src[size], dst[size];
+
+  memset(src, 0, sizeof(src));
+
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    memcpy(dst, src, size);
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+double memcpy100()
+{
+  return memcpy_shared(100);
+}
+
+double memcpy1000()
+{
+  return memcpy_shared(1000);
+}
+
+double memcpy10000()
+{
+  return memcpy_shared(10000);
+}
+
+// Benchmark rjenkins hashing performance on cached data.
+template <int key_length>
+double ceph_str_hash_rjenkins()
+{
+  int count = 100000;
+  char buf[key_length];
+
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++)
+    ceph_str_hash(CEPH_STR_HASH_RJENKINS, buf, sizeof(buf));
+  uint64_t stop = Cycles::rdtsc();
+
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of reading the fine-grain cycle counter.
+double rdtsc_test()
+{
+  int count = 1000000;
+  uint64_t start = Cycles::rdtsc();
+  uint64_t total = 0;
+  for (int i = 0; i < count; i++) {
+    total += Cycles::rdtsc();
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of the Cycles::to_seconds method.
+double perf_cycles_to_seconds()
+{
+  int count = 1000000;
+  double total = 0;
+  uint64_t cycles = 994261;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    total += Cycles::to_seconds(cycles);
+  }
+  uint64_t stop = Cycles::rdtsc();
+  // printf("Result: %.4f\n", total/count);
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of the Cylcles::toNanoseconds method.
+double perf_cycles_to_nanoseconds()
+{
+  int count = 1000000;
+  uint64_t total = 0;
+  uint64_t cycles = 994261;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    total += Cycles::to_nanoseconds(cycles);
+  }
+  uint64_t stop = Cycles::rdtsc();
+  // printf("Result: %lu\n", total/count);
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+
+#ifdef HAVE_SSE
+/**
+ * Prefetch the cache lines containing [object, object + numBytes) into the
+ * processor's caches.
+ * The best docs for this are in the Intel instruction set reference under
+ * PREFETCH.
+ * \param object
+ *      The start of the region of memory to prefetch.
+ * \param num_bytes
+ *      The size of the region of memory to prefetch.
+ */
+static inline void prefetch(const void *object, uint64_t num_bytes)
+{
+    uint64_t offset = reinterpret_cast<uint64_t>(object) & 0x3fUL;
+    const char* p = reinterpret_cast<const char*>(object) - offset;
+    for (uint64_t i = 0; i < offset + num_bytes; i += 64)
+        _mm_prefetch(p + i, _MM_HINT_T0);
+}
+#elif defined(__aarch64__)
+static inline void prefetch(const void *object, uint64_t num_bytes)
+{
+    uint64_t offset = reinterpret_cast<uint64_t>(object) & 0x3fUL;
+    const char* ptr = reinterpret_cast<const char*>(object) - offset;
+    for (uint64_t i = 0; i < offset + num_bytes; i += 64, ptr += 64)
+        asm volatile("prfm pldl1keep, %a0\n" : : "p" (ptr));
+}
+#endif
+
+// Measure the cost of the prefetch instruction.
+double perf_prefetch()
+{
+#if defined(HAVE_SSE) || defined(__aarch64__)
+  uint64_t total_ticks = 0;
+  int count = 10;
+  char buf[16 * 64];
+
+  for (int i = 0; i < count; i++) {
+    PerfHelper::flush_cache();
+    uint64_t start = Cycles::rdtsc();
+    prefetch(&buf[576], 64);
+    prefetch(&buf[0],   64);
+    prefetch(&buf[512], 64);
+    prefetch(&buf[960], 64);
+    prefetch(&buf[640], 64);
+    prefetch(&buf[896], 64);
+    prefetch(&buf[256], 64);
+    prefetch(&buf[704], 64);
+    prefetch(&buf[320], 64);
+    prefetch(&buf[384], 64);
+    prefetch(&buf[128], 64);
+    prefetch(&buf[448], 64);
+    prefetch(&buf[768], 64);
+    prefetch(&buf[832], 64);
+    prefetch(&buf[64],  64);
+    prefetch(&buf[192], 64);
+    uint64_t stop = Cycles::rdtsc();
+    total_ticks += stop - start;
+  }
+  return Cycles::to_seconds(total_ticks) / count / 16;
+#else
+  return -1;
+#endif
+}
+
+#if defined(__x86_64__)
+/**
+ * This function is used to seralize machine instructions so that no
+ * instructions that appear after it in the current thread can run before any
+ * instructions that appear before it. 
+ *
+ * It is useful for putting around rdpmc instructions (to pinpoint cache
+ * misses) as well as before rdtsc instructions, to prevent time pollution from
+ * instructions supposed to be executing before the timer starts.
+ */
+static inline void serialize() {
+    uint32_t eax, ebx, ecx, edx;
+    __asm volatile("cpuid"
+        : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
+        : "a" (1U));
+}
+#endif
+
+// Measure the cost of cpuid
+double perf_serialize() {
+#if defined(__x86_64__)
+  int count = 1000000;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    serialize();
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+#else
+  return -1;
+#endif
+}
+
+// Measure the cost of an lfence instruction.
+double lfence()
+{
+#ifdef HAVE_SSE2
+  int count = 1000000;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    __asm__ __volatile__("lfence" ::: "memory");
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+#elif defined(__aarch64__)
+  int count = 1000000;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    asm volatile("dmb ishld" ::: "memory");
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+#else
+  return -1;
+#endif
+}
+
+// Measure the cost of an sfence instruction.
+double sfence()
+{
+#ifdef HAVE_SSE
+  int count = 1000000;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    __asm__ __volatile__("sfence" ::: "memory");
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+#elif defined(__aarch64__)
+  int count = 1000000;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    asm volatile("dmb ishst" ::: "memory");
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+#else
+  return -1;
+#endif
+}
+
+// Measure the cost of acquiring and releasing a SpinLock (assuming the
+// lock is initially free).
+double test_spinlock()
+{
+  int count = 1000000;
+  ceph::spinlock lock;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    lock.lock();
+    lock.unlock();
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Helper for spawn_thread. This is the main function that the thread executes
+// (intentionally empty).
+class ThreadHelper : public Thread {
+  void *entry() override { return 0; }
+};
+
+// Measure the cost of start and joining with a thread.
+double spawn_thread()
+{
+  int count = 10000;
+  ThreadHelper thread;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    thread.create("thread_helper");
+    thread.join();
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+class FakeContext : public Context {
+ public:
+  void finish(int r) override {}
+};
+
+// Measure the cost of starting and stopping a Dispatch::Timer.
+double perf_timer()
+{
+  int count = 1000000;
+  ceph::mutex lock = ceph::make_mutex("perf_timer::lock");
+  SafeTimer timer(g_ceph_context, lock);
+  FakeContext **c = new FakeContext*[count];
+  for (int i = 0; i < count; i++) {
+    c[i] = new FakeContext();
+  }
+  uint64_t start = Cycles::rdtsc();
+  std::lock_guard l{lock};
+  for (int i = 0; i < count; i++) {
+    if (timer.add_event_after(12345, c[i])) {
+      timer.cancel_event(c[i]);
+    }
+  }
+  uint64_t stop = Cycles::rdtsc();
+  delete[] c;
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of throwing and catching an int. This uses an integer as
+// the value thrown, which is presumably as fast as possible.
+double throw_int()
+{
+  int count = 10000;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    try {
+      throw 0;
+    } catch (int) { // NOLINT
+      // pass
+    }
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of throwing and catching an int from a function call.
+double throw_int_call()
+{
+  int count = 10000;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    try {
+      PerfHelper::throw_int();
+    } catch (int) { // NOLINT
+      // pass
+    }
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of throwing and catching an Exception. This uses an actual
+// exception as the value thrown, which may be slower than throwInt.
+double throw_exception()
+{
+  int count = 10000;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    try {
+      throw buffer::end_of_buffer();
+    } catch (const buffer::end_of_buffer&) {
+      // pass
+    }
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of throwing and catching an Exception from a function call.
+double throw_exception_call()
+{
+  int count = 10000;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    try {
+      PerfHelper::throw_end_of_buffer();
+    } catch (const buffer::end_of_buffer&) {
+      // pass
+    }
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// Measure the cost of pushing a new element on a std::vector, copying
+// from the end to an internal element, and popping the end element.
+double vector_push_pop()
+{
+  int count = 100000;
+  std::vector<int> vector;
+  vector.push_back(1);
+  vector.push_back(2);
+  vector.push_back(3);
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    vector.push_back(i);
+    vector.push_back(i+1);
+    vector.push_back(i+2);
+    vector[2] = vector.back();
+    vector.pop_back();
+    vector[0] = vector.back();
+    vector.pop_back();
+    vector[1] = vector.back();
+    vector.pop_back();
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/(count*3);
+}
+
+// Measure the cost of ceph_clock_now
+double perf_ceph_clock_now()
+{
+  int count = 100000;
+  uint64_t start = Cycles::rdtsc();
+  for (int i = 0; i < count; i++) {
+    ceph_clock_now();
+  }
+  uint64_t stop = Cycles::rdtsc();
+  return Cycles::to_seconds(stop - start)/count;
+}
+
+// The following struct and table define each performance test in terms of
+// a string name and a function that implements the test.
+struct TestInfo {
+  const char* name;             // Name of the performance test; this is
+                                // what gets typed on the command line to
+                                // run the test.
+  double (*func)();             // Function that implements the test;
+                                // returns the time (in seconds) for each
+                                // iteration of that test.
+  const char *description;      // Short description of this test (not more
+                                // than about 40 characters, so the entire
+                                // test output fits on a single line).
+};
+TestInfo tests[] = {
+  {"atomic_int_cmp", atomic_int_cmp,
+    "atomic_t::compare_and_swap"},
+  {"atomic_int_inc", atomic_int_inc,
+    "atomic_t::inc"},
+  {"atomic_int_read", atomic_int_read,
+    "atomic_t::read"},
+  {"atomic_int_set", atomic_int_set,
+    "atomic_t::set"},
+  {"mutex_nonblock", mutex_nonblock,
+    "Mutex lock/unlock (no blocking)"},
+  {"buffer_basic", buffer_basic,
+    "buffer create, add one ptr, delete"},
+  {"buffer_encode_decode", buffer_encode_decode,
+    "buffer create, encode/decode object, delete"},
+  {"buffer_basic_copy", buffer_basic_copy,
+    "buffer create, copy small block, delete"},
+  {"buffer_copy", buffer_copy,
+    "copy out 2 small ptrs from buffer"},
+  {"buffer_encode10", buffer_encode,
+    "buffer encoding 10 structures onto existing ptr"},
+  {"buffer_iterator", buffer_iterator,
+    "iterate over buffer with 5 ptrs"},
+  {"cond_ping_pong", cond_ping_pong,
+    "condition variable round-trip"},
+  {"div32", div32,
+    "32-bit integer division instruction"},
+  {"div64", div64,
+    "64-bit integer division instruction"},
+  {"function_call", function_call,
+    "Call a function that has not been inlined"},
+  {"eventcenter_poll", eventcenter_poll,
+    "EventCenter::process_events (no timers or events)"},
+  {"eventcenter_dispatch", eventcenter_dispatch,
+    "EventCenter::dispatch_event_external latency"},
+  {"memcpy100", memcpy100,
+    "Copy 100 bytes with memcpy"},
+  {"memcpy1000", memcpy1000,
+    "Copy 1000 bytes with memcpy"},
+  {"memcpy10000", memcpy10000,
+    "Copy 10000 bytes with memcpy"},
+  {"ceph_str_hash_rjenkins", ceph_str_hash_rjenkins<16>,
+    "rjenkins hash on 16 byte of data"},
+  {"ceph_str_hash_rjenkins", ceph_str_hash_rjenkins<256>,
+    "rjenkins hash on 256 bytes of data"},
+  {"rdtsc", rdtsc_test,
+    "Read the fine-grain cycle counter"},
+  {"cycles_to_seconds", perf_cycles_to_seconds,
+    "Convert a rdtsc result to (double) seconds"},
+  {"cycles_to_seconds", perf_cycles_to_nanoseconds,
+    "Convert a rdtsc result to (uint64_t) nanoseconds"},
+  {"prefetch", perf_prefetch,
+    "Prefetch instruction"},
+  {"serialize", perf_serialize,
+    "serialize instruction"},
+  {"lfence", lfence,
+    "Lfence instruction"},
+  {"sfence", sfence,
+    "Sfence instruction"},
+  {"spin_lock", test_spinlock,
+    "Acquire/release SpinLock"},
+  {"spawn_thread", spawn_thread,
+    "Start and stop a thread"},
+  {"perf_timer", perf_timer,
+    "Insert and cancel a SafeTimer"},
+  {"throw_int", throw_int,
+    "Throw an int"},
+  {"throw_int_call", throw_int_call,
+    "Throw an int in a function call"},
+  {"throw_exception", throw_exception,
+    "Throw an Exception"},
+  {"throw_exception_call", throw_exception_call,
+    "Throw an Exception in a function call"},
+  {"vector_push_pop", vector_push_pop,
+    "Push and pop a std::vector"},
+  {"ceph_clock_now", perf_ceph_clock_now,
+   "ceph_clock_now function"},
+};
+
+/**
+ * Runs a particular test and prints a one-line result message.
+ *
+ * \param info
+ *      Describes the test to run.
+ */
+void run_test(TestInfo& info)
+{
+  double secs = info.func();
+  int width = printf("%-24s ", info.name);
+  if (secs == -1) {
+    width += printf(" architecture nonsupport ");
+  } else if (secs < 1.0e-06) {
+    width += printf("%8.2fns", 1e09*secs);
+  } else if (secs < 1.0e-03) {
+    width += printf("%8.2fus", 1e06*secs);
+  } else if (secs < 1.0) {
+    width += printf("%8.2fms", 1e03*secs);
+  } else {
+    width += printf("%8.2fs", secs);
+  }
+  printf("%*s %s\n", 32-width, "", info.description);
+}
+
+int main(int argc, char *argv[])
+{
+  vector<const char*> args;
+  argv_to_vec(argc, (const char **)argv, args);
+
+  auto cct = global_init(NULL, args, CEPH_ENTITY_TYPE_CLIENT,
+			 CODE_ENVIRONMENT_UTILITY,
+			 CINIT_FLAG_NO_DEFAULT_CONFIG_FILE);
+  common_init_finish(g_ceph_context);
+  Cycles::init();
+
+  bind_thread_to_cpu(3);
+  if (argc == 1) {
+    // No test names specified; run all tests.
+    for (size_t i = 0; i < sizeof(tests)/sizeof(TestInfo); ++i) {
+      run_test(tests[i]);
+    }
+  } else {
+    // Run only the tests that were specified on the command line.
+    for (int i = 1; i < argc; i++) {
+      bool found_test = false;
+      for (size_t j = 0; j < sizeof(tests)/sizeof(TestInfo); ++j) {
+        if (strcmp(argv[i], tests[j].name) == 0) {
+          found_test = true;
+          run_test(tests[j]);
+          break;
+        }
+      }
+      if (!found_test) {
+        int width = printf("%-24s ??", argv[i]);
+        printf("%*s No such test\n", 32-width, "");
+      }
+    }
+  }
+}