1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
|
/**
* Copyright (C) 2017 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kExecutor;
#include "mongo/platform/basic.h"
#include "mongo/transport/service_executor_synchronous.h"
#include "mongo/db/server_parameters.h"
#include "mongo/stdx/thread.h"
#include "mongo/transport/service_entry_point_utils.h"
#include "mongo/transport/service_executor_task_names.h"
#include "mongo/util/log.h"
#include "mongo/util/net/thread_idle_callback.h"
#include "mongo/util/processinfo.h"
namespace mongo {
namespace transport {
namespace {
// Tasks scheduled with MayRecurse may be called recursively if the recursion depth is below this
// value.
MONGO_EXPORT_SERVER_PARAMETER(synchronousServiceExecutorRecursionLimit, int, 8);
constexpr auto kThreadsRunning = "threadsRunning"_sd;
constexpr auto kExecutorLabel = "executor"_sd;
constexpr auto kExecutorName = "passthrough"_sd;
} // namespace
thread_local std::deque<ServiceExecutor::Task> ServiceExecutorSynchronous::_localWorkQueue = {};
thread_local int ServiceExecutorSynchronous::_localRecursionDepth = 0;
thread_local int64_t ServiceExecutorSynchronous::_localThreadIdleCounter = 0;
ServiceExecutorSynchronous::ServiceExecutorSynchronous(ServiceContext* ctx) {}
Status ServiceExecutorSynchronous::start() {
_numHardwareCores = static_cast<size_t>(ProcessInfo::getNumAvailableCores());
_stillRunning.store(true);
return Status::OK();
}
Status ServiceExecutorSynchronous::shutdown(Milliseconds timeout) {
LOG(3) << "Shutting down passthrough executor";
_stillRunning.store(false);
stdx::unique_lock<stdx::mutex> lock(_shutdownMutex);
bool result = _shutdownCondition.wait_for(lock, timeout.toSystemDuration(), [this]() {
return _numRunningWorkerThreads.load() == 0;
});
return result
? Status::OK()
: Status(ErrorCodes::Error::ExceededTimeLimit,
"passthrough executor couldn't shutdown all worker threads within time limit.");
}
Status ServiceExecutorSynchronous::schedule(Task task,
ScheduleFlags flags,
ServiceExecutorTaskName taskName) {
if (!_stillRunning.load()) {
return Status{ErrorCodes::ShutdownInProgress, "Executor is not running"};
}
if (!_localWorkQueue.empty()) {
/*
* In perf testing we found that yielding after running a each request produced
* at 5% performance boost in microbenchmarks if the number of worker threads
* was greater than the number of available cores.
*/
if (flags & ScheduleFlags::kMayYieldBeforeSchedule) {
if ((_localThreadIdleCounter++ & 0xf) == 0) {
markThreadIdle();
}
if (_numRunningWorkerThreads.loadRelaxed() > _numHardwareCores) {
stdx::this_thread::yield();
}
}
// Execute task directly (recurse) if allowed by the caller as it produced better
// performance in testing. Try to limit the amount of recursion so we don't blow up the
// stack, even though this shouldn't happen with this executor that uses blocking network
// I/O.
if ((flags & ScheduleFlags::kMayRecurse) &&
(_localRecursionDepth < synchronousServiceExecutorRecursionLimit.loadRelaxed())) {
++_localRecursionDepth;
task();
} else {
_localWorkQueue.emplace_back(std::move(task));
}
return Status::OK();
}
// First call to schedule() for this connection, spawn a worker thread that will push jobs
// into the thread local job queue.
LOG(3) << "Starting new executor thread in passthrough mode";
Status status = launchServiceWorkerThread([ this, task = std::move(task) ] {
_numRunningWorkerThreads.addAndFetch(1);
_localWorkQueue.emplace_back(std::move(task));
while (!_localWorkQueue.empty() && _stillRunning.loadRelaxed()) {
_localRecursionDepth = 1;
_localWorkQueue.front()();
_localWorkQueue.pop_front();
}
if (_numRunningWorkerThreads.subtractAndFetch(1) == 0) {
_shutdownCondition.notify_all();
}
});
return status;
}
void ServiceExecutorSynchronous::appendStats(BSONObjBuilder* bob) const {
BSONObjBuilder section(bob->subobjStart("serviceExecutorTaskStats"));
section << kExecutorLabel << kExecutorName << kThreadsRunning
<< static_cast<int>(_numRunningWorkerThreads.loadRelaxed());
}
} // namespace transport
} // namespace mongo
|
