diff --git a/GPU/GPUTracking/Base/GPUReconstruction.cxx b/GPU/GPUTracking/Base/GPUReconstruction.cxx
index ad2ee2e840d00..3ef995b9f9561 100644
--- a/GPU/GPUTracking/Base/GPUReconstruction.cxx
+++ b/GPU/GPUTracking/Base/GPUReconstruction.cxx
@@ -87,6 +87,7 @@ GPUReconstruction::GPUReconstruction(const GPUSettingsDeviceBackend& cfg) : mHos
       throw std::invalid_argument("Cannot be slave to a slave");
     }
     mMaster = cfg.master;
+    mSlaveId = cfg.master->mSlaves.size();
     cfg.master->mSlaves.emplace_back(this);
   }
   param().SetDefaults(mGRPSettings.get());
diff --git a/GPU/GPUTracking/Base/GPUReconstruction.h b/GPU/GPUTracking/Base/GPUReconstruction.h
index f5b39cb370b9e..d5c0b8e828087 100644
--- a/GPU/GPUTracking/Base/GPUReconstruction.h
+++ b/GPU/GPUTracking/Base/GPUReconstruction.h
@@ -190,6 +190,7 @@ class GPUReconstruction
   // Helpers to fetch processors from other shared libraries
   virtual void GetITSTraits(std::unique_ptr<o2::its::TrackerTraits>* trackerTraits, std::unique_ptr<o2::its::VertexerTraits>* vertexerTraits, std::unique_ptr<o2::its::TimeFrame>* timeFrame);
   bool slavesExist() { return mSlaves.size() || mMaster; }
+  int slaveId() { return mSlaveId; }
 
   // Getters / setters for parameters
   DeviceType GetDeviceType() const;
@@ -339,6 +340,7 @@ class GPUReconstruction
 
   GPUReconstruction* mMaster = nullptr;    // Ptr to a GPUReconstruction object serving as master, sharing GPU memory, events, etc.
   std::vector<GPUReconstruction*> mSlaves; // Ptr to slave GPUReconstructions
+  int mSlaveId = -1;                       // Id of this slave (-1 for master)
 
   // Others
   bool mInitialized = false;
diff --git a/GPU/GPUTracking/Global/GPUChainTracking.cxx b/GPU/GPUTracking/Global/GPUChainTracking.cxx
index a3f9b996e070d..f8d4165477220 100644
--- a/GPU/GPUTracking/Global/GPUChainTracking.cxx
+++ b/GPU/GPUTracking/Global/GPUChainTracking.cxx
@@ -378,7 +378,8 @@ int32_t GPUChainTracking::Init()
   }
 
   if (GetProcessingSettings().debugLevel >= 6) {
-    mDebugFile->open(mRec->IsGPU() ? "GPU.out" : "CPU.out");
+    std::string filename = std::string(mRec->IsGPU() ? "GPU" : "CPU") + (mRec->slaveId() != -1 ? (std::string("_slave") + std::to_string(mRec->slaveId())) : std::string(mRec->slavesExist() ? "_master" : "")) + ".out";
+    mDebugFile->open(filename.c_str());
   }
 
   return 0;