Make pmacc checkpointing class

Moves checkpointing simulation control in its own class
Checkpoint class now has a compile time toggle to disable
checkpoint/restart functionality
Simplified restart state management and changed from using bools to an
enum tracking state

Author: ikbuibui

include/picongpu/simulation/control/Simulation.hpp

@@ -39,6 +39,7 @@
 #include "picongpu/random/seed/ISeed.hpp"
 #include "picongpu/simulation/control/DomainAdjuster.hpp"
 #include "picongpu/simulation/control/MovingWindow.hpp"
+#include "picongpu/simulation/control/checkpointingState.hpp"
 #include "picongpu/simulation/stage/AtomicPhysics.hpp"
 #include "picongpu/simulation/stage/Collision.hpp"
 #include "picongpu/simulation/stage/CurrentBackground.hpp"
@@ -69,6 +70,7 @@
 #include <pmacc/particles/traits/FilterByIdentifier.hpp>
 #include <pmacc/random/RNGProvider.hpp>
 #include <pmacc/random/methods/methods.hpp>
+#include <pmacc/simulationControl/Checkpointing.hpp>
 #include <pmacc/simulationControl/SimulationHelper.hpp>
 #include <pmacc/types.hpp>
 #include <pmacc/verify.hpp>
@@ -91,6 +93,8 @@ namespace picongpu
 {
     using namespace pmacc;
 
+    using SimHelper = SimulationHelper<simDim, simulationControl::Checkpointing<checkpointingEnabled>>;
+
     /**
      * Global simulation controller class.
      *
@@ -99,7 +103,7 @@ namespace picongpu
      *
      * @tparam DIM the dimension (2-3) for the simulation
      */
-    class Simulation : public SimulationHelper<simDim>
+    class Simulation : public SimHelper
     {
     public:
         /**
@@ -109,7 +113,7 @@ namespace picongpu
 
         void pluginRegisterHelp(po::options_description& desc) override
         {
-            SimulationHelper<simDim>::pluginRegisterHelp(desc);
+            SimHelper::pluginRegisterHelp(desc);
 
             // clang-format off
             desc.add_options()(
@@ -159,7 +163,7 @@ namespace picongpu
         void startSimulation() override
         {
             if(!skipSimulation)
-                SimulationHelper<simDim>::startSimulation();
+                SimHelper::startSimulation();
         }
 
         nlohmann::json metadata() const
@@ -283,7 +287,7 @@ namespace picongpu
             log<picLog::DOMAINS>("rank %1%; localsize %2%; localoffset %3%;") % myGPUpos.toString()
                 % gridSizeLocal.toString() % gridOffset.toString();
 
-            SimulationHelper<simDim>::pluginLoad();
+            SimHelper::pluginLoad();
 
             GridLayout<simDim> layout(gridSizeLocal, GuardSize::toRT() * SuperCellSize::toRT());
             cellDescription = std::make_unique<MappingDesc>(layout.sizeND(), DataSpace<simDim>(GuardSize::toRT()));
@@ -304,7 +308,7 @@ namespace picongpu
         {
             DataConnector& dc = Environment<>::get().DataConnector();
 
-            SimulationHelper<simDim>::pluginUnload();
+            SimHelper::pluginUnload();
 
             /** unshare all registered ISimulationData sets
              *
@@ -456,38 +460,7 @@ namespace picongpu
             if(initialiserController)
             {
                 initialiserController->printInformation();
-                if(this->restartRequested)
-                {
-                    /* we do not require '--checkpoint.restart.step' if a master checkpoint file is found */
-                    if(this->restartStep < 0)
-                    {
-                        std::vector<uint32_t> checkpoints = readCheckpointMasterFile();
-
-                        if(checkpoints.empty())
-                        {
-                            if(this->tryRestart == false)
-                            {
-                                throw std::runtime_error(
-                                    "Restart failed. You must provide the "
-                                    "'--checkpoint.restart.step' argument. See picongpu --help.");
-                            }
-                            else
-                            {
-                                // no checkpoint found: start simulation from scratch
-                                this->restartRequested = false;
-                            }
-                        }
-                        else
-                            this->restartStep = checkpoints.back();
-                    }
-                }
-
-                if(this->restartRequested)
-                {
-                    initialiserController->restart((uint32_t) this->restartStep, this->restartDirectory);
-                    step = this->restartStep;
-                }
-                else
+                if(!this->checkpointing.restart(initialiserController, step))
                 {
                     simulation::stage::ParticleInit{}(step);
                     (*atomicPhysics).fixAtomicStateInit(*cellDescription);
@@ -547,13 +520,13 @@ namespace picongpu
         void dumpOneStep(uint32_t currentStep) override
         {
             fieldBackground->toDumpState(currentStep);
-            SimulationHelper<simDim>::dumpOneStep(currentStep);
+            SimHelper::dumpOneStep(currentStep);
         }
 
         void notifyPlugins(uint32_t currentStep) override
         {
             fieldBackground->toPluginState(currentStep);
-            SimulationHelper<simDim>::notifyPlugins(currentStep);
+            SimHelper::notifyPlugins(currentStep);
         }
 
         void movingWindowCheck(uint32_t currentStep) override

include/picongpu/simulation/control/checkpointingState.hpp

@@ -0,0 +1,30 @@
+/* Copyright 2025 Tapish Narwal
+ *
+ * This file is part of PIConGPU.
+ *
+ * PIConGPU is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * PIConGPU is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with PIConGPU.
+ * If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+namespace picongpu
+{
+    static constexpr bool checkpointingEnabled =
+#if (ENABLE_OPENPMD == 1)
+        true;
+#else
+        false;
+#endif
+} // namespace picongpu