GPU TPC: improved GPU TPC track-model decoding #13122
Conversation
…reams, unattached clusters input transfer in separate stream
…rs per kernel call
|
REQUEST FOR PRODUCTION RELEASES: This will add The following labels are available |
| } | ||
| mIOPtrs.clustersNative = mClusterNativeAccess.get(); | ||
| mClusterNativeAccess->clustersLinear = mInputsHost->mPclusterNativeOutput; | ||
| mClusterNativeAccess->setOffsetPtrs(); | ||
|
|
||
| runKernel<GPUTPCDecompressionKernels, GPUTPCDecompressionKernels::step1unattached>(GetGridAuto(inputStream)); | ||
| unsigned int batchSize = doGPU ? 6 : NSLICES; | ||
| for (unsigned int iSlice = 0; iSlice < NSLICES; iSlice = iSlice + batchSize) { |
There was a problem hiding this comment.
You could do an outer OMP loop on the CPU, and set a nested OMP nThreads for the inner loop that is used for the kernel, as done here:
| bool toGPU = true; | ||
| runKernel<GPUMemClean16>({GetGridAutoStep(inputStream, RecoStep::TPCDecompression), krnlRunRangeNone, &mEvents->init}, DecompressorShadow.mNativeClustersIndex, NSLICES * GPUCA_ROW_COUNT * sizeof(DecompressorShadow.mNativeClustersIndex[0])); | ||
| std::exclusive_scan(cmprClsHost.nTrackClusters, cmprClsHost.nTrackClusters + cmprClsHost.nTracks, Decompressor.mAttachedClustersOffsets, 0u); // computing clusters offsets for first kernel | ||
| int nStreams = doGPU ? mRec->NStreams() - 1 : 1; |
There was a problem hiding this comment.
nStreams here could perhaps depend on the data size. For very small cases, one might want to use less than nStreams() - 1, or even just one.
Perhaps, you also want std::max(1, NStreams() - 1), just in case nStreams could be 1 one a GPU model (which is currently not the case).
Hides DMA transfer latencies in GPU TPC track-model decoding, pipelining data transfers and kernel calls to multiple streams.