erebus

annotate liberebus/src/threadpool.cc @ 32:b1fc96c71bcc

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- lambert BRDF importance sampling - UI + commandline arguments - font rendering for showing status/progress
author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 07 Jun 2014 13:36:36 +0300
parents 53a98c148bf8
children d15ee526daa6
rev   line source
nuclear@26 1 #include <algorithm>
nuclear@26 2 #include <chrono>
nuclear@26 3 #include "threadpool.h"
nuclear@26 4
nuclear@26 5 using namespace std::chrono;
nuclear@26 6
nuclear@26 7 ThreadPool::ThreadPool(int num_threads)
nuclear@26 8 {
nuclear@26 9 quit = false;
nuclear@26 10 qsize = 0;
nuclear@26 11 nactive = 0;
nuclear@26 12
nuclear@26 13 if(num_threads == -1) {
nuclear@26 14 num_threads = std::thread::hardware_concurrency();
nuclear@26 15 }
nuclear@26 16
nuclear@26 17 printf("creating thread pool with %d threads\n", num_threads);
nuclear@26 18
nuclear@26 19 thread = new std::thread[num_threads];
nuclear@26 20 for(int i=0; i<num_threads; i++) {
nuclear@26 21 thread[i] = std::thread(&ThreadPool::thread_func, this);
nuclear@31 22
nuclear@31 23 #ifdef _MSC_VER
nuclear@31 24 /* detach the thread to avoid having to join them in the destructor, which
nuclear@31 25 * causes a deadlock in msvc implementation when called after main returns
nuclear@31 26 */
nuclear@31 27 thread[i].detach();
nuclear@31 28 #endif
nuclear@26 29 }
nuclear@26 30 this->num_threads = num_threads;
nuclear@26 31 }
nuclear@26 32
nuclear@26 33 ThreadPool::~ThreadPool()
nuclear@26 34 {
nuclear@31 35 #ifdef _MSC_VER
nuclear@31 36 workq_mutex.lock();
nuclear@31 37 workq.clear();
nuclear@31 38 qsize = 0;
nuclear@31 39 workq_mutex.unlock();
nuclear@31 40 #endif
nuclear@31 41
nuclear@26 42 quit = true;
nuclear@26 43 workq_condvar.notify_all();
nuclear@26 44
nuclear@26 45 printf("ThreadPool: waiting for %d worker threads to stop ", num_threads);
nuclear@26 46 fflush(stdout);
nuclear@31 47 #ifndef _MSC_VER
nuclear@26 48 for(int i=0; i<num_threads; i++) {
nuclear@26 49 thread[i].join();
nuclear@26 50 putchar('.');
nuclear@26 51 fflush(stdout);
nuclear@26 52 }
nuclear@31 53 #else
nuclear@31 54 // spin until all threads are done...
nuclear@31 55 std::unique_lock<std::mutex> lock(workq_mutex);
nuclear@31 56 while(nactive > 0) {
nuclear@31 57 lock.unlock();
nuclear@31 58 std::this_thread::sleep_for(std::chrono::milliseconds(128));
nuclear@31 59 putchar('.');
nuclear@31 60 fflush(stdout);
nuclear@31 61 lock.lock();
nuclear@31 62 }
nuclear@31 63 #endif // _MSC_VER
nuclear@31 64
nuclear@26 65 putchar('\n');
nuclear@31 66 delete [] thread;
nuclear@26 67 }
nuclear@26 68
nuclear@26 69 void ThreadPool::add_work(std::function<void ()> func)
nuclear@26 70 {
nuclear@26 71 add_work(func, std::function<void ()>{});
nuclear@26 72 }
nuclear@26 73
nuclear@26 74 void ThreadPool::add_work(std::function<void ()> work_func, std::function<void ()> done_func)
nuclear@26 75 {
nuclear@26 76 std::unique_lock<std::mutex> lock(workq_mutex);
nuclear@26 77 workq.push_back(WorkItem{work_func, done_func});
nuclear@26 78 ++qsize;
nuclear@26 79 workq_condvar.notify_all();
nuclear@26 80 }
nuclear@26 81
nuclear@26 82 int ThreadPool::queued() const
nuclear@26 83 {
nuclear@26 84 std::unique_lock<std::mutex> lock(workq_mutex);
nuclear@26 85 return qsize;
nuclear@26 86 }
nuclear@26 87
nuclear@26 88 int ThreadPool::active() const
nuclear@26 89 {
nuclear@26 90 std::unique_lock<std::mutex> lock(workq_mutex);
nuclear@26 91 return nactive;
nuclear@26 92 }
nuclear@26 93
nuclear@26 94 int ThreadPool::pending() const
nuclear@26 95 {
nuclear@26 96 std::unique_lock<std::mutex> lock(workq_mutex);
nuclear@26 97 return nactive + qsize;
nuclear@26 98 }
nuclear@26 99
nuclear@26 100 long ThreadPool::wait()
nuclear@26 101 {
nuclear@26 102 auto start_time = steady_clock::now();
nuclear@26 103
nuclear@26 104 std::unique_lock<std::mutex> lock(workq_mutex);
nuclear@26 105 done_condvar.wait(lock, [this](){ return nactive == 0 && workq.empty(); });
nuclear@26 106
nuclear@26 107 auto dur = steady_clock::now() - start_time;
nuclear@26 108 return duration_cast<milliseconds>(dur).count();
nuclear@26 109 }
nuclear@26 110
nuclear@26 111 long ThreadPool::wait(long timeout)
nuclear@26 112 {
nuclear@26 113 auto start_time = steady_clock::now();
nuclear@26 114 duration<long, std::milli> dur, timeout_dur(std::max(timeout, 5L));
nuclear@26 115
nuclear@26 116 std::unique_lock<std::mutex> lock(workq_mutex);
nuclear@26 117 while(timeout_dur.count() > 0 && (nactive > 0 || !workq.empty())) {
nuclear@26 118 if(done_condvar.wait_for(lock, timeout_dur) == std::cv_status::timeout) {
nuclear@26 119 break;
nuclear@26 120 }
nuclear@26 121 dur = duration_cast<milliseconds>(steady_clock::now() - start_time);
nuclear@26 122 timeout_dur = milliseconds(std::max(timeout, 5L)) - dur;
nuclear@26 123 }
nuclear@26 124
nuclear@26 125 /*printf("waited for: %ld ms (%ld req) (na %d,qs %d,em %s)\n", dur.count(), timeout,
nuclear@26 126 nactive, qsize, workq.empty() ? "true" : "false");*/
nuclear@26 127 return dur.count();
nuclear@26 128 }
nuclear@26 129
nuclear@26 130 void ThreadPool::thread_func()
nuclear@26 131 {
nuclear@26 132 std::unique_lock<std::mutex> lock(workq_mutex);
nuclear@26 133 for(;;) {
nuclear@26 134 if(quit) break;
nuclear@26 135
nuclear@26 136 workq_condvar.wait(lock);
nuclear@26 137
nuclear@26 138 while(!quit && !workq.empty()) {
nuclear@26 139 WorkItem witem = workq.front();
nuclear@26 140 workq.pop_front();
nuclear@26 141 ++nactive;
nuclear@26 142 --qsize;
nuclear@26 143 lock.unlock();
nuclear@26 144
nuclear@26 145 witem.work();
nuclear@26 146 if(witem.done) {
nuclear@26 147 witem.done();
nuclear@26 148 }
nuclear@26 149
nuclear@26 150 lock.lock();
nuclear@26 151 --nactive;
nuclear@26 152 done_condvar.notify_all();
nuclear@26 153 }
nuclear@26 154 }
nuclear@26 155 }
nuclear@26 156