  We present an efficient open-source implementation of the multiparticle
collision dynamics (MPCD) algorithm that scales to run on hundreds of graphics
processing units (GPUs). We especially focus on optimizations for modern GPU
architectures and communication patterns between multiple GPUs. We show that a
mixed-precision computing model can improve performance compared to a fully
double-precision model while still providing good numerical accuracy. We report
weak and strong scaling benchmarks of a reference MPCD solvent and a benchmark
of a polymer solution with research-relevant interactions and system size. Our
MPCD software enables simulations of mesoscale hydrodynamics at length and time
scales that would be otherwise challenging or impossible to access.
