Geant4 Version: 11.3.2
Operating System: Ubuntu 24.04 LTS (Noble Numbat)
Compiler/Version: g++ (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0
CMake Version: 3.28.3
Hi 
I have updated my application to run in multithreading mode. After some fixes, it now completes the job without crashing, but I don’t see any performance improvement. It is taking the same amount of time as the serial application.
I tried to understand why, but I cannot find any reason. Are there any suggestions?
I will attach here some part of the code that can be related to the issue:
RunAction.cpp
#include "RunAction.h"
#include "RunMetadata.h"
#include <filesystem>
RunAction::RunAction()
{
// set printing event number per each 100 events
G4RunManager::GetRunManager()->SetPrintProgress(1000);
fHistManager = HistogramManager::Instance();
}
RunAction::~RunAction()
{
delete fHistManager;
}
void RunAction::BeginOfRunAction(const G4Run *run)
{
HistogramManager::Instance()->Book();
G4RunManager *runManager = G4RunManager::GetRunManager();
// inform the runManager to save random number seed
runManager->SetRandomNumberStore(false);
}
void RunAction::EndOfRunAction(const G4Run *run)
{
G4int nEvents = run->GetNumberOfEvent();
HistogramManager::Instance()->Close();
auto analysisManager = G4AnalysisManager::Instance();
auto runMetadata = RunMetadata::Instance();
runMetadata->SetNumberOfEvents(nEvents);
std::string filename = analysisManager->GetFileName();
std::string stem = std::filesystem::path(filename).stem().string(); // filename without extension
std::filesystem::path parent_path = std::filesystem::path(filename).parent_path(); // return the path to the file location
std::string jsonFilename = (parent_path / stem).string() + ".json";
runMetadata->SaveToJson(jsonFilename);
}
All the creation and filing of nTuples is done in this class:
HistogramManager.cpp
#include "HistogramManager.h"
#include "G4SystemOfUnits.hh"
#include "MyHit.h"
#include "Names.h"
// Define the thread-local singleton pointer
G4ThreadLocal HistogramManager *HistogramManager::fInstance = nullptr;
HistogramManager *HistogramManager::Instance()
{
if (!fInstance)
{
fInstance = new HistogramManager();
}
return fInstance;
}
HistogramManager::HistogramManager()
{
G4AnalysisManager::Instance()->SetDefaultFileType("root"); // Default file type
G4AnalysisManager::Instance()->SetFileName("output"); // Default file name
G4AnalysisManager::Instance()->SetVerboseLevel(1);
// Only merge in MT mode to avoid warning when running in Sequential mode
#ifdef G4MULTITHREADED
G4cout << "[INFO] SetNtupleMerging set to True!" << G4endl;
G4AnalysisManager::Instance()->SetNtupleMerging(true);
#endif
}
}
HistogramManager::~HistogramManager()
{
}
void HistogramManager::Book()
{
if (fIsBooked)
return;
Open();
CreateNTuples();
fIsBooked = true;
G4cout << "[HistogramManager] Histograms and ntuples booked." << G4endl;
}
void HistogramManager::Open()
{
G4AnalysisManager::Instance()->OpenFile(); // uses macro-set filename
G4cout << "[HistogramManager] File opened." << G4endl;
}
void HistogramManager::Close()
{
G4AnalysisManager::Instance()->Write();
G4AnalysisManager::Instance()->CloseFile();
G4cout << "[HistogramManager] File written and closed." << G4endl;
}
// -------------------------------------------------------------
// --------------- C R E A T E M E T H O D S ---------------
// -------------------------------------------------------------
void HistogramManager::CreateNTuples()
{
//! NTuple: Hit info
G4AnalysisManager::Instance()->CreateNtuple(Names::nTupleHitData.name, "Run Hit data"); // ID: 1
G4AnalysisManager::Instance()->CreateNtupleDColumn(Names::nTupleHitData.id, Names::cEnergyDeposited.name);
// .... OTHER CREATE COLUMNS.....
G4AnalysisManager::Instance()->FinishNtuple();
//! NTuple: Event summary
G4AnalysisManager::Instance()->CreateNtuple(Names::nTupleEventSummary.name, "Event summary"); // ID: 2
// ... CREATE COLUMNS ...
G4AnalysisManager::Instance()->FinishNtuple();
}
// ----------------------------------------------------------
// --------------- F I L L M E T H O D S ---------------
// ----------------------------------------------------------
void HistogramManager::FillHitData(const MyHit *hit)
{
// Fill the Ntuple: Hit Data
G4AnalysisManager::Instance()->FillNtupleDColumn(Names::nTupleHitData.id, Names::cEnergyDeposited.id, hit->GetEdep());
// .... OTHER FILL COMMANDS .....
G4AnalysisManager::Instance()->AddNtupleRow(Names::nTupleHitData.id);
}
void HistogramManager::FillEventSummary(G4double totalEdep, G4int nHits, G4int nTracks, int id)
{
G4AnalysisManager::Instance()->FillNtupleDColumn(Names::nTupleEventSummary.id, Names::cTotEdep.id, totalEdep / MeV);
// .... OTHER FILL COMMANDS .....
G4AnalysisManager::Instance()->AddNtupleRow(Names::nTupleEventSummary.id);
}
And they are called in the EventAction.cpp
#include "EventAction.h"
#include "MyHit.h"
#include "G4THitsCollection.hh"
#include "G4SDManager.hh"
#include "G4AnalysisManager.hh"
#include "HistogramManager.h"
#include "G4Event.hh"
#include "Names.h"
#include <set>
// Called automatically by Geant4 at the begin of each event
void EventAction::BeginOfEventAction(const G4Event *) {}
// Called automatically by Geant4 at the end of each event
void EventAction::EndOfEventAction(const G4Event *event)
{
// Retrieve the hit collections container for this event
G4HCofThisEvent *hce = event->GetHCofThisEvent();
// If no hit collections exist, skip this event
if (!hce)
return;
// Static variables: get collection IDs once
static G4int hcIDActive = -1;
if (hcIDActive < 0)
hcIDActive = G4SDManager::GetSDMpointer()->GetCollectionID(Names::activeAreaSensitiveDetector + "_thread" + std::to_string(G4Threading::G4GetThreadId()) + "/" + Names::activeAreaHitsCollection);
// Get the actual hits collections for this event
auto hitsCollectionActive = static_cast<G4THitsCollection<MyHit> *>(hce->GetHC(hcIDActive));
// If neither collection found, skip
if (!hitsCollectionActive)
return;
// Initialize per-event variables using the active area collection
G4double totalEdep = 0.; // Sum of all energy deposited in this event (active area)
G4int numHits = hitsCollectionActive->entries(); // Number of hits recorded in active area
G4double totalChargedEdep = 0.; // Total energy deposited by charged particles in active area
std::set<G4int> trackIDs;
auto analysisManager = G4AnalysisManager::Instance();
auto histogramManager = HistogramManager::Instance();
// Loop over hits in the active area collection
for (G4int iHit = 0; iHit < numHits; ++iHit)
{
auto hit = (*hitsCollectionActive)[iHit];
trackIDs.insert(hit->GetTrackID());
if (hit->GetIsActiveArea())
{
// Account only E Dep in the active Area
totalEdep += hit->GetEdep();
}
histogramManager->FillHitData(hit);
}
// Avoid saving events with no energy deposition
histogramManager->FillEventSummary(totalEdep, numHits, trackIDs.size(), event->GetEventID());
}
Perhaps I’m doing something wrong, but I’m unable to identify the issue. I’m saving the output to .root file and some run metadata to a .json file format.
Many thanks for considering my request.
Michael