GPU: Use automatic grid size estimation for resolve kernel

Author: davidrohr

GPU/Common/GPUDefGPUParameters.h

@@ -96,7 +96,7 @@
   #define GPUCA_LB_GPUTPCGMMergerResolve_step0 256
   #define GPUCA_LB_GPUTPCGMMergerResolve_step1 256
   #define GPUCA_LB_GPUTPCGMMergerResolve_step2 256
-  #define GPUCA_LB_GPUTPCGMMergerResolve_step3 256
+  #define GPUCA_LB_GPUTPCGMMergerResolve_step3 256, 4
   #define GPUCA_LB_GPUTPCGMMergerClearLinks 256
   #define GPUCA_LB_GPUTPCGMMergerMergeWithinPrepare 256
   #define GPUCA_LB_GPUTPCGMMergerMergeSlicesPrepare 256, 2

GPU/GPUTracking/Global/GPUChainTracking.cxx

@@ -1645,11 +1645,10 @@ void GPUChainTracking::RunTPCTrackingMerger_MergeBorderTracks(char withinSlice,
 
 void GPUChainTracking::RunTPCTrackingMerger_Resolve(char useOrigTrackParam, char mergeAll, GPUReconstruction::krnlDeviceType deviceType)
 {
-  runKernel<GPUTPCGMMergerResolve, 0>(GetGridBlk(BlockCount(), 0, deviceType), krnlRunRangeNone, krnlEventNone);
-  runKernel<GPUTPCGMMergerResolve, 1>(GetGridBlk(BlockCount(), 0, deviceType), krnlRunRangeNone, krnlEventNone);
-  runKernel<GPUTPCGMMergerResolve, 2>(GetGridBlk(BlockCount(), 0, deviceType), krnlRunRangeNone, krnlEventNone);
-  // TODO: Determine number of blocks from block size to fully occupy gpu
-  runKernel<GPUTPCGMMergerResolve, 3>(GetGridBlk(BlockCount() * 4, 0, deviceType), krnlRunRangeNone, krnlEventNone, useOrigTrackParam, mergeAll);
+  runKernel<GPUTPCGMMergerResolve, 0>(GetGridAuto(0, deviceType), krnlRunRangeNone, krnlEventNone);
+  runKernel<GPUTPCGMMergerResolve, 1>(GetGridAuto(0, deviceType), krnlRunRangeNone, krnlEventNone);
+  runKernel<GPUTPCGMMergerResolve, 2>(GetGridAuto(0, deviceType), krnlRunRangeNone, krnlEventNone);
+  runKernel<GPUTPCGMMergerResolve, 3>(GetGridAuto(0, deviceType), krnlRunRangeNone, krnlEventNone, useOrigTrackParam, mergeAll);
 }
 
 int GPUChainTracking::RunTPCTrackingMerger(bool synchronizeOutput)