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/**
* Copyright (C) 2022-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include <benchmark/benchmark.h>
#include <string>
#include <vector>
#include "mongo/db/concurrency/locker_noop_client_observer.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/service_context.h"
#include "mongo/util/concurrency/ticketholder.h"
#include "mongo/util/tick_source_mock.h"
namespace mongo {
namespace {
static int kTickets = 128;
static int kThreadMin = 16;
static int kThreadMax = 1024;
static int kLowPriorityAdmissionBypassThreshold = 100;
static TicketHolder::WaitMode waitMode = TicketHolder::WaitMode::kUninterruptible;
// For a given benchmark, specifies the AdmissionContext::Priority of ticket admissions
enum class AdmissionsPriority {
// All admissions must be AdmissionContext::Priority::kNormal.
kNormal,
// Admissions may vary between AdmissionContext::Priority::kNormal and
// AdmissionContext::Priority::kLow.
kNormalAndLow,
// All admissions must be AdmissionContext::Priority::kLow.
kLow,
};
template <typename TicketHolderImpl>
class TicketHolderFixture {
public:
std::unique_ptr<TicketHolder> ticketHolder;
std::vector<ServiceContext::UniqueClient> clients;
std::vector<ServiceContext::UniqueOperationContext> opCtxs;
TicketHolderFixture(int threads, ServiceContext* serviceContext) {
if constexpr (std::is_same_v<PriorityTicketHolder, TicketHolderImpl>) {
ticketHolder = std::make_unique<TicketHolderImpl>(
kTickets, kLowPriorityAdmissionBypassThreshold, serviceContext);
} else {
ticketHolder = std::make_unique<TicketHolderImpl>(kTickets, serviceContext);
}
for (int i = 0; i < threads; ++i) {
clients.push_back(
serviceContext->makeClient(str::stream() << "test client for thread " << i));
opCtxs.push_back(clients[i]->makeOperationContext());
}
}
};
static Mutex isReadyMutex;
static stdx::condition_variable isReadyCv;
static bool isReady = false;
template <class TicketHolderImpl, AdmissionsPriority admissionsPriority>
void BM_acquireAndRelease(benchmark::State& state) {
static std::unique_ptr<TicketHolderFixture<TicketHolderImpl>> ticketHolder;
static ServiceContext::UniqueServiceContext serviceContext;
{
stdx::unique_lock lk(isReadyMutex);
if (state.thread_index == 0) {
serviceContext = ServiceContext::make();
serviceContext->setTickSource(std::make_unique<TickSourceMock<Microseconds>>());
serviceContext->registerClientObserver(std::make_unique<LockerNoopClientObserver>());
ticketHolder = std::make_unique<TicketHolderFixture<TicketHolderImpl>>(
state.threads, serviceContext.get());
isReady = true;
isReadyCv.notify_all();
} else {
isReadyCv.wait(lk, [&] { return isReady; });
}
}
double acquired = 0;
AdmissionContext::Priority priority = [&] {
switch (admissionsPriority) {
case AdmissionsPriority::kNormal:
return AdmissionContext::Priority::kNormal;
case AdmissionsPriority::kLow:
return AdmissionContext::Priority::kLow;
case AdmissionsPriority::kNormalAndLow: {
return (state.thread_index % 2) == 0 ? AdmissionContext::Priority::kNormal
: AdmissionContext::Priority::kLow;
}
default:
MONGO_UNREACHABLE;
}
}();
TicketHolderFixture<TicketHolderImpl>* fixture = ticketHolder.get();
for (auto _ : state) {
AdmissionContext admCtx;
admCtx.setPriority(priority);
auto opCtx = fixture->opCtxs[state.thread_index].get();
{
auto ticket = fixture->ticketHolder->waitForTicket(opCtx, &admCtx, waitMode);
state.PauseTiming();
sleepmicros(1);
acquired++;
state.ResumeTiming();
}
}
state.counters["Acquired"] = benchmark::Counter(acquired, benchmark::Counter::kIsRate);
state.counters["AcquiredPerThread"] =
benchmark::Counter(acquired, benchmark::Counter::kAvgThreadsRate);
if (state.thread_index == 0) {
ticketHolder.reset();
serviceContext.reset();
isReady = false;
}
}
// The 'AdmissionsPriority' has no effect on SemaphoreTicketHolder performance because the
// SemaphoreTicketHolder treaats all operations the same, regardless of their specified priority.
// However, the benchmarks between the SemaphoreTicketHolder and the PriorityTicketHolder are only
// comparable when all admissions are of normal priority.
BENCHMARK_TEMPLATE(BM_acquireAndRelease, SemaphoreTicketHolder, AdmissionsPriority::kNormal)
->Threads(kThreadMin)
->Threads(kTickets)
->Threads(kThreadMax);
BENCHMARK_TEMPLATE(BM_acquireAndRelease, PriorityTicketHolder, AdmissionsPriority::kNormal)
->Threads(kThreadMin)
->Threads(kTickets)
->Threads(kThreadMax);
// Low priority operations are expected to take longer to acquire a ticket because they are forced
// to take a slower path than normal priority operations.
BENCHMARK_TEMPLATE(BM_acquireAndRelease, PriorityTicketHolder, AdmissionsPriority::kLow)
->Threads(kThreadMin)
->Threads(kTickets)
->Threads(kThreadMax);
// This benchmark is intended for comparisons between different iterations of the
// PriorityTicketHolder over time.
//
// Since it is known low priority operations will be less performant than normal priority
// operations, the aggregate performance over operations will be lower, and cannot be accurately
// compared to TicketHolderImpl benchmarks with only normal priority operations.
BENCHMARK_TEMPLATE(BM_acquireAndRelease, PriorityTicketHolder, AdmissionsPriority::kNormalAndLow)
->Threads(kThreadMin)
->Threads(kTickets)
->Threads(kThreadMax);
} // namespace
} // namespace mongo
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