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// Copyright 2019 The Emscripten Authors. All rights reserved.
// Emscripten is available under two separate licenses, the MIT license and the
// University of Illinois/NCSA Open Source License. Both these licenses can be
// found in the LICENSE file.
#include <thread>
#include <math.h>
#include <emscripten.h>
#include <assert.h>
#include <iostream>
extern "C" {
//Create a thread that does some work
void EMSCRIPTEN_KEEPALIVE spawn_a_thread() {
std::thread( [] {
double d=0;
for (int i=0; i<10; i++) //simulate work
d += (i%2 ? sqrt((int)(rand())) : (-1)*sqrt((int)(rand())));
} ).detach();
}
//Check that the number of workers is less than the number of spawned threads.
void EMSCRIPTEN_KEEPALIVE count_threads(int num_threads_spawned, int num_threads_spawned_extra) {
num_threads_spawned += num_threads_spawned_extra;
int num_workers = EM_ASM_INT({
return PThread.runningWorkers.length + PThread.unusedWorkers.length;
});
std::cout <<
"Worker pool size: " << num_workers <<
", Number of threads spawned: " << num_threads_spawned
<< "." << std::endl;
assert(num_threads_spawned_extra != 0);
assert(num_workers < num_threads_spawned);
emscripten_force_exit(0);
}
}
//Spawn a detached thread every 0.1s. After 0.3s Check that the number of workers are less than the number of spawned threads
int main(int argc, char** argv) {
EM_ASM(
let thread_check = 0;
const max_thread_check = 5; //fail the test if the number of threads doesn't go down after checking this many times
const threads_to_spawn = 3;
let threads_to_spawn_extra = 0;
//Spawn some detached threads
for (let i=0; i<threads_to_spawn; i++) {
setTimeout(() => { _spawn_a_thread(); }, i*100);
}
//Check if a worker is free every threads_to_spawn*100 ms, or until max_thread_check is exceeded
const SpawnMoreThreads = setInterval(() => {
if (PThread.unusedWorkers.length > 0) { //Spawn a thread if a worker is available
_spawn_a_thread();
threads_to_spawn_extra++;
}
if (thread_check++ > max_thread_check || threads_to_spawn_extra > 0) {
clearInterval(SpawnMoreThreads);
_count_threads(threads_to_spawn, threads_to_spawn_extra);
}
}, threads_to_spawn*100);
);
emscripten_exit_with_live_runtime();
}
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