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Commit d43e710c authored by Phil Willoughby's avatar Phil Willoughby Committed by Facebook Github Bot 6
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Convert a polling loop to a futex wait 

Summary:Add a new method to MPMCQueue:
```
template <class Clock, typename... Args>
  bool tryWriteUntil(const std::chrono::time_point<Clock>& when,
                     Args&&... args) noexcept
```
This allows you to write producers which terminate reliably in the absence of consumers.

Returns `true` if `args` was enqueued, `false` otherwise.

`Clock` must be one of the types supported by the underlying call to `folly::detail::Futex::futexWaitUntil`; at time of writing these are `std::chrono::steady_clock` and `std::chrono::system_clock`.

Reviewed By: nbronson

Differential Revision: D2895574

fb-gh-sync-id: bdfabcd043191c149f1271e30ffc28476cc8a36e
shipit-source-id: bdfabcd043191c149f1271e30ffc28476cc8a36e
parent f509d73d
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Showing with 366 additions and 79 deletions
folly/MPMCQueue.h
View file @ d43e710c
......@@ -284,6 +284,21 @@ class MPMCQueue : boost::noncopyable {
}
}
template <class Clock, typename... Args>
bool tryWriteUntil(const std::chrono::time_point<Clock>& when,
Args&&... args) noexcept {
uint64_t ticket;
if (tryObtainPromisedPushTicketUntil(ticket, when)) {
// we have pre-validated that the ticket won't block, or rather that
// it won't block longer than it takes another thread to dequeue an
// element from the slot it identifies.
enqueueWithTicket(ticket, std::forward<Args>(args)...);
return true;
} else {
return false;
}
}
/// If the queue is not full, enqueues and returns true, otherwise
/// returns false. Unlike write this method can be blocked by another
/// thread, specifically a read that has linearized (been assigned
......@@ -471,6 +486,28 @@ class MPMCQueue : boost::noncopyable {
}
}
/// Tries until when to obtain a push ticket for which
/// SingleElementQueue::enqueue won't block. Returns true on success, false
/// on failure.
/// ticket is filled on success AND failure.
template <class Clock>
bool tryObtainPromisedPushTicketUntil(
uint64_t& ticket, const std::chrono::time_point<Clock>& when) noexcept {
bool deadlineReached = false;
while (!deadlineReached) {
if (tryObtainPromisedPushTicket(ticket)) {
return true;
}
// ticket is a blocking ticket until the preceding ticket has been
// processed: wait until this ticket's turn arrives. We have not reserved
// this ticket so we will have to re-attempt to get a non-blocking ticket
// if we wake up before we time-out.
deadlineReached = !slots_[idx(ticket)].tryWaitForEnqueueTurnUntil(
turn(ticket), pushSpinCutoff_, (ticket % kAdaptationFreq) == 0, when);
}
return false;
}
/// Tries to obtain a push ticket which can be satisfied if all
/// in-progress pops complete. This function does not block, but
/// blocking may be required when using the returned ticket if some
......@@ -482,6 +519,7 @@ class MPMCQueue : boost::noncopyable {
auto numPops = popTicket_.load(std::memory_order_acquire); // B
// n will be negative if pops are pending
int64_t n = numPushes - numPops;
rv = numPushes;
if (n >= static_cast<ssize_t>(capacity_)) {
// Full, linearize at B. We don't need to recheck the read we
// performed at A, because if numPushes was stale at B then the
......@@ -489,7 +527,6 @@ class MPMCQueue : boost::noncopyable {
return false;
}
if (pushTicket_.compare_exchange_strong(numPushes, numPushes + 1)) {
rv = numPushes;
return true;
}
}
......@@ -597,7 +634,7 @@ struct SingleElementQueue {
template <typename = typename std::enable_if<
(folly::IsRelocatable<T>::value &&
boost::has_nothrow_constructor<T>::value) ||
std::is_nothrow_constructible<T,T&&>::value>::type>
std::is_nothrow_constructible<T, T&&>::value>::type>
void enqueue(const uint32_t turn,
Atom<uint32_t>& spinCutoff,
const bool updateSpinCutoff,
......@@ -611,6 +648,20 @@ struct SingleElementQueue {
ImplByMove, ImplByRelocation>::type());
}
/// Waits until either:
/// 1: the dequeue turn preceding the given enqueue turn has arrived
/// 2: the given deadline has arrived
/// Case 1 returns true, case 2 returns false.
template <class Clock>
bool tryWaitForEnqueueTurnUntil(
const uint32_t turn,
Atom<uint32_t>& spinCutoff,
const bool updateSpinCutoff,
const std::chrono::time_point<Clock>& when) noexcept {
return sequencer_.tryWaitForTurn(
turn * 2, spinCutoff, updateSpinCutoff, &when);
}
bool mayEnqueue(const uint32_t turn) const noexcept {
return sequencer_.isTurn(turn * 2);
}
......
folly/detail/TurnSequencer.h
View file @ d43e710c
......@@ -82,10 +82,10 @@ struct TurnSequencer {
/// See tryWaitForTurn
/// Requires that `turn` is not a turn in the past.
void waitForTurn(const uint32_t turn,
Atom<uint32_t>& spinCutoff,
const bool updateSpinCutoff) noexcept {
Atom<uint32_t>& spinCutoff,
const bool updateSpinCutoff) noexcept {
bool success = tryWaitForTurn(turn, spinCutoff, updateSpinCutoff);
(void) success;
(void)success;
assert(success);
}
......@@ -99,9 +99,15 @@ struct TurnSequencer {
/// before blocking and will adjust spinCutoff based on the results,
/// otherwise it will spin for at most spinCutoff spins.
/// Returns true if the wait succeeded, false if the turn is in the past
/// or the absTime time value is not nullptr and is reached before the turn
/// arrives
template <class Clock = std::chrono::steady_clock,
class Duration = typename Clock::duration>
bool tryWaitForTurn(const uint32_t turn,
Atom<uint32_t>& spinCutoff,
const bool updateSpinCutoff) noexcept {
Atom<uint32_t>& spinCutoff,
const bool updateSpinCutoff,
const std::chrono::time_point<Clock, Duration>* absTime =
nullptr) noexcept {
uint32_t prevThresh = spinCutoff.load(std::memory_order_relaxed);
const uint32_t effectiveSpinCutoff =
updateSpinCutoff || prevThresh == 0 ? kMaxSpins : prevThresh;
......@@ -142,7 +148,15 @@ struct TurnSequencer {
continue;
}
}
state_.futexWait(new_state, futexChannel(turn));
if (absTime) {
auto futexResult =
state_.futexWaitUntil(new_state, *absTime, futexChannel(turn));
if (futexResult == FutexResult::TIMEDOUT) {
return false;
}
} else {
state_.futexWait(new_state, futexChannel(turn));
}
}
if (updateSpinCutoff || prevThresh == 0) {
......@@ -179,9 +193,9 @@ struct TurnSequencer {
while (true) {
assert(state == encode(turn << kTurnShift, decodeMaxWaitersDelta(state)));
uint32_t max_waiter_delta = decodeMaxWaitersDelta(state);
uint32_t new_state = encode(
(turn + 1) << kTurnShift,
max_waiter_delta == 0 ? 0 : max_waiter_delta - 1);
uint32_t new_state =
encode((turn + 1) << kTurnShift,
max_waiter_delta == 0 ? 0 : max_waiter_delta - 1);
if (state_.compare_exchange_strong(state, new_state)) {
if (max_waiter_delta != 0) {
state_.futexWake(std::numeric_limits<int>::max(),
......@@ -227,9 +241,7 @@ struct TurnSequencer {
/// Returns the bitmask to pass futexWait or futexWake when communicating
/// about the specified turn
int futexChannel(uint32_t turn) const noexcept {
return 1 << (turn & 31);
}
int futexChannel(uint32_t turn) const noexcept { return 1 << (turn & 31); }
uint32_t decodeCurrentSturn(uint32_t state) const noexcept {
return state & ~kWaitersMask;
......@@ -240,7 +252,7 @@ struct TurnSequencer {
}
uint32_t encode(uint32_t currentSturn, uint32_t maxWaiterD) const noexcept {
return currentSturn | std::min(uint32_t{ kWaitersMask }, maxWaiterD);
return currentSturn | std::min(uint32_t{kWaitersMask}, maxWaiterD);
}
};
......
folly/test/MPMCQueueTest.cpp
View file @ d43e710c
......@@ -35,6 +35,14 @@ FOLLY_ASSUME_FBVECTOR_COMPATIBLE_1(boost::intrusive_ptr);
using namespace folly;
using namespace detail;
using namespace test;
using std::chrono::time_point;
using std::chrono::steady_clock;
using std::chrono::seconds;
using std::chrono::milliseconds;
using std::string;
using std::make_unique;
using std::unique_ptr;
using std::vector;
typedef DeterministicSchedule DSched;
......@@ -61,7 +69,7 @@ void run_mt_sequencer_test(int numThreads, int numOps, uint32_t init) {
Atom<uint32_t> spinThreshold(0);
int prev = -1;
std::vector<std::thread> threads(numThreads);
vector<std::thread> threads(numThreads);
for (int i = 0; i < numThreads; ++i) {
threads[i] = DSched::thread(std::bind(run_mt_sequencer_thread<Atom>,
numThreads, numOps, init, std::ref(seq), std::ref(spinThreshold),
......@@ -102,6 +110,12 @@ void runElementTypeTest(T&& src) {
cq.blockingRead(dest);
EXPECT_TRUE(cq.write(std::move(dest)));
EXPECT_TRUE(cq.read(dest));
auto soon1 = std::chrono::system_clock::now() + std::chrono::seconds(1);
EXPECT_TRUE(cq.tryWriteUntil(soon1, std::move(dest)));
EXPECT_TRUE(cq.read(dest));
auto soon2 = std::chrono::steady_clock::now() + std::chrono::seconds(1);
EXPECT_TRUE(cq.tryWriteUntil(soon2, std::move(dest)));
EXPECT_TRUE(cq.read(dest));
}
struct RefCounted {
......@@ -132,9 +146,9 @@ void intrusive_ptr_release(RefCounted const* p) {
TEST(MPMCQueue, lots_of_element_types) {
runElementTypeTest(10);
runElementTypeTest(std::string("abc"));
runElementTypeTest(std::make_pair(10, std::string("def")));
runElementTypeTest(std::vector<std::string>{ { "abc" } });
runElementTypeTest(string("abc"));
runElementTypeTest(std::make_pair(10, string("def")));
runElementTypeTest(vector<string>{{"abc"}});
runElementTypeTest(std::make_shared<char>('a'));
runElementTypeTest(folly::make_unique<char>('a'));
runElementTypeTest(boost::intrusive_ptr<RefCounted>(new RefCounted));
......@@ -237,7 +251,7 @@ void runTryEnqDeqTest(int numThreads, int numOps) {
MPMCQueue<int,Atom> cq(numThreads);
uint64_t n = numOps;
std::vector<std::thread> threads(numThreads);
vector<std::thread> threads(numThreads);
std::atomic<uint64_t> sum(0);
for (int t = 0; t < numThreads; ++t) {
threads[t] = DSched::thread(std::bind(runTryEnqDeqThread<Atom>,
......@@ -294,9 +308,59 @@ uint64_t nowMicro() {
}
template <typename Q>
std::string producerConsumerBench(Q&& queue, std::string qName,
int numProducers, int numConsumers,
int numOps, bool ignoreContents = false) {
struct WriteMethodCaller {
WriteMethodCaller() {}
virtual ~WriteMethodCaller() = default;
virtual bool callWrite(Q& q, int i) = 0;
virtual string methodName() = 0;
};
template <typename Q>
struct BlockingWriteCaller : public WriteMethodCaller<Q> {
bool callWrite(Q& q, int i) override {
q.blockingWrite(i);
return true;
}
string methodName() override { return "blockingWrite"; }
};
template <typename Q>
struct WriteIfNotFullCaller : public WriteMethodCaller<Q> {
bool callWrite(Q& q, int i) override { return q.writeIfNotFull(i); }
string methodName() override { return "writeIfNotFull"; }
};
template <typename Q>
struct WriteCaller : public WriteMethodCaller<Q> {
bool callWrite(Q& q, int i) override { return q.write(i); }
string methodName() override { return "write"; }
};
template <typename Q,
class Clock = steady_clock,
class Duration = typename Clock::duration>
struct TryWriteUntilCaller : public WriteMethodCaller<Q> {
const Duration duration_;
explicit TryWriteUntilCaller(Duration&& duration) : duration_(duration) {}
bool callWrite(Q& q, int i) override {
auto then = Clock::now() + duration_;
return q.tryWriteUntil(then, i);
}
string methodName() override {
return folly::sformat(
"tryWriteUntil({}ms)",
std::chrono::duration_cast<milliseconds>(duration_).count());
}
};
template <typename Q>
string producerConsumerBench(Q&& queue,
string qName,
int numProducers,
int numConsumers,
int numOps,
WriteMethodCaller<Q>& writer,
bool ignoreContents = false) {
Q& q = queue;
struct rusage beginUsage;
......@@ -306,17 +370,20 @@ std::string producerConsumerBench(Q&& queue, std::string qName,
uint64_t n = numOps;
std::atomic<uint64_t> sum(0);
std::atomic<uint64_t> failed(0);
std::vector<std::thread> producers(numProducers);
vector<std::thread> producers(numProducers);
for (int t = 0; t < numProducers; ++t) {
producers[t] = DSched::thread([&,t]{
for (int i = t; i < numOps; i += numProducers) {
q.blockingWrite(i);
while (!writer.callWrite(q, i)) {
++failed;
}
}
});
}
std::vector<std::thread> consumers(numConsumers);
vector<std::thread> consumers(numConsumers);
for (int t = 0; t < numConsumers; ++t) {
consumers[t] = DSched::thread([&,t]{
uint64_t localSum = 0;
......@@ -348,27 +415,76 @@ std::string producerConsumerBench(Q&& queue, std::string qName,
uint64_t nanosPer = (1000 * (endMicro - beginMicro)) / n;
long csw = endUsage.ru_nvcsw + endUsage.ru_nivcsw -
(beginUsage.ru_nvcsw + beginUsage.ru_nivcsw);
uint64_t failures = failed;
return folly::format(
"{}, {} producers, {} consumers => {} nanos/handoff, {} csw / {} handoff",
qName, numProducers, numConsumers, nanosPer, csw, n).str();
return folly::sformat(
"{}, {} {} producers, {} consumers => {} nanos/handoff, {} csw / {} "
"handoff, {} failures",
qName,
numProducers,
writer.methodName(),
numConsumers,
nanosPer,
csw,
n,
failures);
}
TEST(MPMCQueue, mt_prod_cons_deterministic) {
// we use the Bench method, but perf results are meaningless under DSched
DSched sched(DSched::uniform(0));
producerConsumerBench(MPMCQueue<int,DeterministicAtomic>(10),
"", 1, 1, 1000);
producerConsumerBench(MPMCQueue<int,DeterministicAtomic>(100),
"", 10, 10, 1000);
producerConsumerBench(MPMCQueue<int,DeterministicAtomic>(10),
"", 1, 1, 1000);
producerConsumerBench(MPMCQueue<int,DeterministicAtomic>(100),
"", 10, 10, 1000);
producerConsumerBench(MPMCQueue<int,DeterministicAtomic>(1),
"", 10, 10, 1000);
vector<unique_ptr<WriteMethodCaller<MPMCQueue<int, DeterministicAtomic>>>>
callers;
callers.emplace_back(
make_unique<BlockingWriteCaller<MPMCQueue<int, DeterministicAtomic>>>());
callers.emplace_back(
make_unique<WriteIfNotFullCaller<MPMCQueue<int, DeterministicAtomic>>>());
callers.emplace_back(
make_unique<WriteCaller<MPMCQueue<int, DeterministicAtomic>>>());
callers.emplace_back(
make_unique<TryWriteUntilCaller<MPMCQueue<int, DeterministicAtomic>>>(
milliseconds(1)));
callers.emplace_back(
make_unique<TryWriteUntilCaller<MPMCQueue<int, DeterministicAtomic>>>(
seconds(2)));
for (const auto& caller : callers) {
LOG(INFO)
<< producerConsumerBench(MPMCQueue<int, DeterministicAtomic>(10),
"MPMCQueue<int, DeterministicAtomic>(10)",
1,
1,
1000,
*caller);
LOG(INFO)
<< producerConsumerBench(MPMCQueue<int, DeterministicAtomic>(100),
"MPMCQueue<int, DeterministicAtomic>(100)",
10,
10,
1000,
*caller);
LOG(INFO)
<< producerConsumerBench(MPMCQueue<int, DeterministicAtomic>(10),
"MPMCQueue<int, DeterministicAtomic>(10)",
1,
1,
1000,
*caller);
LOG(INFO)
<< producerConsumerBench(MPMCQueue<int, DeterministicAtomic>(100),
"MPMCQueue<int, DeterministicAtomic>(100)",
10,
10,
1000,
*caller);
LOG(INFO) << producerConsumerBench(MPMCQueue<int, DeterministicAtomic>(1),
"MPMCQueue<int, DeterministicAtomic>(1)",
10,
10,
1000,
*caller);
}
}
#define PC_BENCH(q, np, nc, ...) \
......@@ -376,38 +492,71 @@ TEST(MPMCQueue, mt_prod_cons_deterministic) {
TEST(MPMCQueue, mt_prod_cons) {
int n = 100000;
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10), 1, 1, n);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10), 10, 1, n);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10), 1, 10, n);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10), 10, 10, n);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10000), 1, 1, n);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10000), 10, 1, n);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10000), 1, 10, n);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10000), 10, 10, n);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(100000), 32, 100, n);
vector<unique_ptr<WriteMethodCaller<MPMCQueue<int>>>> callers;
callers.emplace_back(make_unique<BlockingWriteCaller<MPMCQueue<int>>>());
callers.emplace_back(make_unique<WriteIfNotFullCaller<MPMCQueue<int>>>());
callers.emplace_back(make_unique<WriteCaller<MPMCQueue<int>>>());
callers.emplace_back(
make_unique<TryWriteUntilCaller<MPMCQueue<int>>>(milliseconds(1)));
callers.emplace_back(
make_unique<TryWriteUntilCaller<MPMCQueue<int>>>(seconds(2)));
for (const auto& caller : callers) {
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10), 1, 1, n, *caller);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10), 10, 1, n, *caller);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10), 1, 10, n, *caller);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10), 10, 10, n, *caller);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10000), 1, 1, n, *caller);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10000), 10, 1, n, *caller);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10000), 1, 10, n, *caller);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(10000), 10, 10, n, *caller);
LOG(INFO) << PC_BENCH(MPMCQueue<int>(100000), 32, 100, n, *caller);
}
}
TEST(MPMCQueue, mt_prod_cons_emulated_futex) {
int n = 100000;
LOG(INFO) << PC_BENCH((MPMCQueue<int,EmulatedFutexAtomic>(10)), 1, 1, n);
LOG(INFO) << PC_BENCH((MPMCQueue<int,EmulatedFutexAtomic>(10)), 10, 1, n);
LOG(INFO) << PC_BENCH((MPMCQueue<int,EmulatedFutexAtomic>(10)), 1, 10, n);
LOG(INFO) << PC_BENCH((MPMCQueue<int,EmulatedFutexAtomic>(10)), 10, 10, n);
LOG(INFO) << PC_BENCH((MPMCQueue<int,EmulatedFutexAtomic>(10000)), 1, 1, n);
LOG(INFO) << PC_BENCH((MPMCQueue<int,EmulatedFutexAtomic>(10000)), 10, 1, n);
LOG(INFO) << PC_BENCH((MPMCQueue<int,EmulatedFutexAtomic>(10000)), 1, 10, n);
LOG(INFO) << PC_BENCH((MPMCQueue<int,EmulatedFutexAtomic>(10000)), 10, 10, n);
LOG(INFO)
<< PC_BENCH((MPMCQueue<int,EmulatedFutexAtomic>(100000)), 32, 100, n);
}
template <template<typename> class Atom>
void runNeverFailThread(
int numThreads,
int n, /*numOps*/
MPMCQueue<int, Atom>& cq,
std::atomic<uint64_t>& sum,
int t) {
vector<unique_ptr<WriteMethodCaller<MPMCQueue<int, EmulatedFutexAtomic>>>>
callers;
callers.emplace_back(
make_unique<BlockingWriteCaller<MPMCQueue<int, EmulatedFutexAtomic>>>());
callers.emplace_back(
make_unique<WriteIfNotFullCaller<MPMCQueue<int, EmulatedFutexAtomic>>>());
callers.emplace_back(
make_unique<WriteCaller<MPMCQueue<int, EmulatedFutexAtomic>>>());
callers.emplace_back(
make_unique<TryWriteUntilCaller<MPMCQueue<int, EmulatedFutexAtomic>>>(
milliseconds(1)));
callers.emplace_back(
make_unique<TryWriteUntilCaller<MPMCQueue<int, EmulatedFutexAtomic>>>(
seconds(2)));
for (const auto& caller : callers) {
LOG(INFO) << PC_BENCH(
(MPMCQueue<int, EmulatedFutexAtomic>(10)), 1, 1, n, *caller);
LOG(INFO) << PC_BENCH(
(MPMCQueue<int, EmulatedFutexAtomic>(10)), 10, 1, n, *caller);
LOG(INFO) << PC_BENCH(
(MPMCQueue<int, EmulatedFutexAtomic>(10)), 1, 10, n, *caller);
LOG(INFO) << PC_BENCH(
(MPMCQueue<int, EmulatedFutexAtomic>(10)), 10, 10, n, *caller);
LOG(INFO) << PC_BENCH(
(MPMCQueue<int, EmulatedFutexAtomic>(10000)), 1, 1, n, *caller);
LOG(INFO) << PC_BENCH(
(MPMCQueue<int, EmulatedFutexAtomic>(10000)), 10, 1, n, *caller);
LOG(INFO) << PC_BENCH(
(MPMCQueue<int, EmulatedFutexAtomic>(10000)), 1, 10, n, *caller);
LOG(INFO) << PC_BENCH(
(MPMCQueue<int, EmulatedFutexAtomic>(10000)), 10, 10, n, *caller);
LOG(INFO) << PC_BENCH(
(MPMCQueue<int, EmulatedFutexAtomic>(100000)), 32, 100, n, *caller);
}
}
template <template <typename> class Atom>
void runNeverFailThread(int numThreads,
int n, /*numOps*/
MPMCQueue<int, Atom>& cq,
std::atomic<uint64_t>& sum,
int t) {
uint64_t threadSum = 0;
for (int i = t; i < n; i += numThreads) {
// enq + deq
......@@ -421,19 +570,23 @@ void runNeverFailThread(
sum += threadSum;
}
template <template<typename> class Atom>
template <template <typename> class Atom>
uint64_t runNeverFailTest(int numThreads, int numOps) {
// always #enq >= #deq
MPMCQueue<int,Atom> cq(numThreads);
MPMCQueue<int, Atom> cq(numThreads);
uint64_t n = numOps;
auto beginMicro = nowMicro();
std::vector<std::thread> threads(numThreads);
vector<std::thread> threads(numThreads);
std::atomic<uint64_t> sum(0);
for (int t = 0; t < numThreads; ++t) {
threads[t] = DSched::thread(std::bind(runNeverFailThread<Atom>,
numThreads, n, std::ref(cq), std::ref(sum), t));
numThreads,
n,
std::ref(cq),
std::ref(sum),
t));
}
for (auto& t : threads) {
DSched::join(t);
......@@ -445,29 +598,29 @@ uint64_t runNeverFailTest(int numThreads, int numOps) {
}
TEST(MPMCQueue, mt_never_fail) {
int nts[] = { 1, 3, 100 };
int nts[] = {1, 3, 100};
int n = 100000;
for (int nt : nts) {
uint64_t elapsed = runNeverFailTest<std::atomic>(nt, n);
LOG(INFO) << (elapsed * 1000.0) / (n * 2) << " nanos per op with "
<< nt << " threads";
LOG(INFO) << (elapsed * 1000.0) / (n * 2) << " nanos per op with " << nt
<< " threads";
}
}
TEST(MPMCQueue, mt_never_fail_emulated_futex) {
int nts[] = { 1, 3, 100 };
int nts[] = {1, 3, 100};
int n = 100000;
for (int nt : nts) {
uint64_t elapsed = runNeverFailTest<EmulatedFutexAtomic>(nt, n);
LOG(INFO) << (elapsed * 1000.0) / (n * 2) << " nanos per op with "
<< nt << " threads";
LOG(INFO) << (elapsed * 1000.0) / (n * 2) << " nanos per op with " << nt
<< " threads";
}
}
TEST(MPMCQueue, mt_never_fail_deterministic) {
int nts[] = { 3, 10 };
int nts[] = {3, 10};
long seed = 0; // nowMicro() % 10000;
LOG(INFO) << "using seed " << seed;
......@@ -485,6 +638,77 @@ TEST(MPMCQueue, mt_never_fail_deterministic) {
}
}
template <class Clock, template <typename> class Atom>
void runNeverFailUntilThread(int numThreads,
int n, /*numOps*/
MPMCQueue<int, Atom>& cq,
std::atomic<uint64_t>& sum,
int t) {
uint64_t threadSum = 0;
for (int i = t; i < n; i += numThreads) {
// enq + deq
auto soon = Clock::now() + std::chrono::seconds(1);
EXPECT_TRUE(cq.tryWriteUntil(soon, i));
int dest = -1;
EXPECT_TRUE(cq.readIfNotEmpty(dest));
EXPECT_TRUE(dest >= 0);
threadSum += dest;
}
sum += threadSum;
}
template <class Clock, template <typename> class Atom>
uint64_t runNeverFailTest(int numThreads, int numOps) {
// always #enq >= #deq
MPMCQueue<int, Atom> cq(numThreads);
uint64_t n = numOps;
auto beginMicro = nowMicro();
vector<std::thread> threads(numThreads);
std::atomic<uint64_t> sum(0);
for (int t = 0; t < numThreads; ++t) {
threads[t] = DSched::thread(std::bind(runNeverFailUntilThread<Clock, Atom>,
numThreads,
n,
std::ref(cq),
std::ref(sum),
t));
}
for (auto& t : threads) {
DSched::join(t);
}
EXPECT_TRUE(cq.isEmpty());
EXPECT_EQ(n * (n - 1) / 2 - sum, 0);
return nowMicro() - beginMicro;
}
TEST(MPMCQueue, mt_never_fail_until_system) {
int nts[] = {1, 3, 100};
int n = 100000;
for (int nt : nts) {
uint64_t elapsed =
runNeverFailTest<std::chrono::system_clock, std::atomic>(nt, n);
LOG(INFO) << (elapsed * 1000.0) / (n * 2) << " nanos per op with " << nt
<< " threads";
}
}
TEST(MPMCQueue, mt_never_fail_until_steady) {
int nts[] = {1, 3, 100};
int n = 100000;
for (int nt : nts) {
uint64_t elapsed =
runNeverFailTest<std::chrono::steady_clock, std::atomic>(nt, n);
LOG(INFO) << (elapsed * 1000.0) / (n * 2) << " nanos per op with " << nt
<< " threads";
}
}
enum LifecycleEvent {
NOTHING = -1,
DEFAULT_CONSTRUCTOR,
......
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