Figure 14

Speedup of HLT tracking algorithm executed on GPUs and CPUs compared to the offline tracker normalized to a single core and corrected for the serial processing part that the CPU contributes to GPU tracking as a function of the input data size expressed in terms of the number of TPC clusters. The plus markers show the speedup as a function of the number of TPC clusters with the HLT tracking executed on the CPU. The cross(astrisk) markers show the speedup obtained with the tracking executed on a older(newer) GPU.