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#include "TFile.h"
#include "TTree.h"
#include "TBranch.h"
#include "TClass.h"
#include "TThread.h"
#include "TVirtualStreamerInfo.h"
#include "TList.h"
#include "TMap.h"
#include "TObjString.h"
#include "TH1F.h"
#include <memory>
#include <cassert>
#include <iostream>
#include <thread>
#include <atomic>
#include <sstream>
std::atomic<bool> waitToStart{true};
std::atomic<unsigned int> countdownToWrite{0};
void printHelp(const char* iName, int iDefaultNThreads) {
std::cout << iName << " [number of threads] [gDebug value]\n\n"
<< "[number of threads] number of threads to use in test\n"
<< "[gDebug value] value of gDebug to pass to ROOT (gDebug=1 is useful)\n"
<< "If no arguments are given " << iDefaultNThreads << " threads will be used" << std::endl;
}
std::pair<int, int> parseOptionsForNumberOfThreadsAndgDebug(int argc, char** argv) {
constexpr int kDefaultNThreads = 4;
int kDefaultgDebug = gDebug;
int nThreads = kDefaultNThreads;
int newGDebug = kDefaultgDebug;
if (argc >= 2) {
if (strcmp("-h", argv[1]) == 0) {
printHelp(argv[0], kDefaultNThreads);
exit(0);
}
nThreads = atoi(argv[1]);
}
if (argc == 3) {
newGDebug = atoi(argv[2]);
}
if (argc > 3) {
printHelp(argv[0], kDefaultNThreads);
exit(1);
}
return std::make_pair(nThreads, newGDebug);
}
TList* createList() {
auto returnValue = new TList();
for (unsigned int i = 0; i < 10; ++i) {
returnValue->Add(new TList());
returnValue->Add(new TMap());
returnValue->Add(new TObjString());
returnValue->Add(new TH1F());
returnValue->Add(new TH1D());
}
return returnValue;
}
int main(int argc, char** argv) {
auto values = parseOptionsForNumberOfThreadsAndgDebug(argc, argv);
const int kNThreads = values.first;
countdownToWrite = kNThreads;
gDebug = values.second;
//Tell Root we want to be multi-threaded
TThread::Initialize();
//When threading, also have to keep ROOT from logging all TObjects into a list
TObject::SetObjectStat(false);
//Have to avoid having Streamers modify themselves after they have been used
TVirtualStreamerInfo::Optimize(false);
std::vector<std::shared_ptr<std::thread>> threads;
threads.reserve(kNThreads);
for (int i = 0; i < kNThreads; ++i) {
threads.push_back(std::make_shared<std::thread>(std::thread([i]() {
static thread_local TThread s_thread_guard;
std::stringstream nameStream;
nameStream << "write_thread_" << i << ".root";
auto theList = createList();
while (waitToStart)
;
TFile f(nameStream.str().c_str(), "RECREATE", "test");
auto listTree = new TTree("TheList", "TheList");
listTree->Branch("theList", "TList", &theList);
--countdownToWrite;
while (countdownToWrite != 0)
;
for (unsigned int i = 0; i < 100; ++i) {
listTree->Fill();
}
f.Write();
f.Close();
})));
}
waitToStart = false;
for (auto& t : threads) {
t->join();
}
return 0;
}
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