GPU TPC: Fix parallel linking of global tracks to local tracks

AliceO2Group · Feb 26, 2024 · b162f2e · b162f2e
1 parent 2d17052
commit b162f2e
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Showing 2 changed files with 4 additions and 1 deletion.
diff --git a/GPU/GPUTracking/Merger/GPUTPCGMMerger.cxx b/GPU/GPUTracking/Merger/GPUTPCGMMerger.cxx
@@ -646,7 +646,9 @@ GPUd() void GPUTPCGMMerger::LinkGlobalTracks(int nBlocks, int nThreads, int iBlo
   for (int itr = SliceTrackInfoGlobalFirst(0) + iBlock * nThreads + iThread; itr < SliceTrackInfoGlobalLast(NSLICES - 1); itr += nThreads * nBlocks) {
     GPUTPCGMSliceTrack& globalTrack = mSliceTrackInfos[itr];
     GPUTPCGMSliceTrack& localTrack = mSliceTrackInfos[globalTrack.LocalTrackId()];
-    localTrack.SetGlobalTrackId(localTrack.GlobalTrackId(0) != -1, itr); // Todo: broken in parallel
+    if (localTrack.GlobalTrackId(0) != -1 || !CAMath::AtomicCAS(&localTrack.GlobalTrackIds()[0], -1, itr)) {
+      localTrack.SetGlobalTrackId(1, itr);
+    }
   }
 }
 

diff --git a/GPU/GPUTracking/Merger/GPUTPCGMSliceTrack.h b/GPU/GPUTracking/Merger/GPUTPCGMSliceTrack.h
@@ -63,6 +63,7 @@ class GPUTPCGMSliceTrack
   GPUd() void SetLocalTrackId(int v) { mLocalTrackId = v; }
   GPUd() int GlobalTrackId(int n) const { return mGlobalTrackIds[n]; }
   GPUd() void SetGlobalTrackId(int n, int v) { mGlobalTrackIds[n] = v; }
+  GPUd() int* GlobalTrackIds() { return mGlobalTrackIds; }
 
   GPUd() float MaxClusterZT() const { return CAMath::Max(mClusterZT[0], mClusterZT[1]); }
   GPUd() float MinClusterZT() const { return CAMath::Min(mClusterZT[0], mClusterZT[1]); }