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
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
|
/**
* @file threadpool.cpp
* @author Nat Goodspeed
* @date 2021-10-21
* @brief Implementation for threadpool.
*
* $LicenseInfo:firstyear=2021&license=viewerlgpl$
* Copyright (c) 2021, Linden Research, Inc.
* $/LicenseInfo$
*/
// Precompiled header
#include "linden_common.h"
// associated header
#include "threadpool.h"
// STL headers
// std headers
// external library headers
// other Linden headers
#include "commoncontrol.h"
#include "llcoros.h"
#include "llerror.h"
#include "llevents.h"
#include "llsd.h"
#include "stringize.h"
#include <boost/fiber/algo/round_robin.hpp>
/*****************************************************************************
* Custom fiber scheduler for worker threads
*****************************************************************************/
// As of 2022-12-06, each of our worker threads only runs a single (default)
// fiber: we don't launch explicit fibers within worker threads, nor do we
// anticipate doing so. So a worker thread that's simply waiting for incoming
// tasks should really sleep a little. Override the default fiber scheduler to
// implement that.
struct sleepy_robin: public boost::fibers::algo::round_robin
{
virtual void suspend_until( std::chrono::steady_clock::time_point const&) noexcept
{
#if LL_WINDOWS
// round_robin holds a std::condition_variable, and
// round_robin::suspend_until() calls
// std::condition_variable::wait_until(). On Windows, that call seems
// busier than it ought to be. Try just sleeping.
Sleep(1);
#else
// currently unused other than windows, but might as well have something here
// different units than Sleep(), but we actually just want to sleep for any de-minimis duration
usleep(1);
#endif
}
virtual void notify() noexcept
{
// Since our Sleep() call above will wake up on its own, we need not
// take any special action to wake it.
}
};
/*****************************************************************************
* ThreadPoolBase
*****************************************************************************/
LL::ThreadPoolBase::ThreadPoolBase(const std::string& name,
size_t threads,
WorkQueueBase* queue,
bool auto_shutdown):
super(name),
mName("ThreadPool:" + name),
mThreadCount(getConfiguredWidth(name, threads)),
mQueue(queue),
mAutomaticShutdown(auto_shutdown)
{}
void LL::ThreadPoolBase::start()
{
for (size_t i = 0; i < mThreadCount; ++i)
{
std::string tname{ stringize(mName, ':', (i+1), '/', mThreadCount) };
mThreads.emplace_back(tname, [this, tname]()
{
LL_PROFILER_SET_THREAD_NAME(tname.c_str());
run(tname);
});
}
if (!mAutomaticShutdown)
{
// Some threads, like main window's might need to run a bit longer
// to wait for a proper shutdown message
return;
}
// When the app is shutting down, close the queue and join the workers.
mStopListener = LLCoros::getStopListener(
mName,
[this](const LLSD& status)
{
// viewer is starting shutdown -- proclaim the end is nigh!
LL_DEBUGS("ThreadPool") << mName << " saw " << status << LL_ENDL;
close();
});
}
LL::ThreadPoolBase::~ThreadPoolBase()
{
close();
if (!LLEventPumps::wasDeleted())
{
LLEventPumps::instance().obtain("LLApp").stopListening(mName);
}
}
void LL::ThreadPoolBase::close()
{
// mQueue might have been closed already, but in any case we must join or
// detach each of our threads before destroying the mThreads vector.
LL_DEBUGS("ThreadPool") << mName << " closing queue and joining threads" << LL_ENDL;
mQueue->close();
for (auto& pair: mThreads)
{
if (pair.second.joinable())
{
LL_DEBUGS("ThreadPool") << mName << " waiting on thread " << pair.first << LL_ENDL;
pair.second.join();
}
}
LL_DEBUGS("ThreadPool") << mName << " shutdown complete" << LL_ENDL;
}
void LL::ThreadPoolBase::run(const std::string& name)
{
#if LL_WINDOWS
// Try using sleepy_robin fiber scheduler.
boost::fibers::use_scheduling_algorithm<sleepy_robin>();
#endif // LL_WINDOWS
LL_DEBUGS("ThreadPool") << name << " starting" << LL_ENDL;
run();
LL_DEBUGS("ThreadPool") << name << " stopping" << LL_ENDL;
}
void LL::ThreadPoolBase::run()
{
mQueue->runUntilClose();
}
//static
size_t LL::ThreadPoolBase::getConfiguredWidth(const std::string& name, size_t dft)
{
LLSD poolSizes;
try
{
poolSizes = LL::CommonControl::get("Global", "ThreadPoolSizes");
// "ThreadPoolSizes" is actually a map containing the sizes of
// interest -- or should be, if this process has an
// LLViewerControlListener instance and its settings include
// "ThreadPoolSizes". If we failed to retrieve it, perhaps we're in a
// program that doesn't define that, or perhaps there's no such
// setting, or perhaps we're asking too early, before the LLEventAPI
// itself has been instantiated. In any of those cases, it seems worth
// warning.
if (! poolSizes.isDefined())
{
// Note: we don't warn about absence of an override key for a
// particular ThreadPool name, that's fine. This warning is about
// complete absence of a ThreadPoolSizes setting, which we expect
// in a normal viewer session.
LL_WARNS("ThreadPool") << "No 'ThreadPoolSizes' setting for ThreadPool '"
<< name << "'" << LL_ENDL;
}
}
catch (const LL::CommonControl::Error& exc)
{
// We don't want ThreadPool to *require* LLViewerControlListener.
// Just log it and carry on.
LL_WARNS("ThreadPool") << "Can't check 'ThreadPoolSizes': " << exc.what() << LL_ENDL;
}
LL_DEBUGS("ThreadPool") << "ThreadPoolSizes = " << poolSizes << LL_ENDL;
// LLSD treats an undefined value as an empty map when asked to retrieve a
// key, so we don't need this to be conditional.
LLSD sizeSpec{ poolSizes[name] };
// We retrieve sizeSpec as LLSD, rather than immediately as LLSD::Integer,
// so we can distinguish the case when it's undefined.
return sizeSpec.isInteger() ? sizeSpec.asInteger() : dft;
}
//static
size_t LL::ThreadPoolBase::getWidth(const std::string& name, size_t dft)
{
auto instance{ getInstance(name) };
if (instance)
{
return instance->getWidth();
}
else
{
return getConfiguredWidth(name, dft);
}
}
|
