Improved the intra-GPU load balancing

[alexxy/gromacs.git] / src / gromacs / mdlib / nbnxn_cuda / nbnxn_cuda_data_mgmt.cu

diff --git a/src/gromacs/mdlib/nbnxn_cuda/nbnxn_cuda_data_mgmt.cu b/src/gromacs/mdlib/nbnxn_cuda/nbnxn_cuda_data_mgmt.cu
index 2923125d8a97265e71b1f854a0d461be48f6f106..edef45e66669e0ae76e57c0f341ab59fca3c6b38 100644 (file)
--- a/src/gromacs/mdlib/nbnxn_cuda/nbnxn_cuda_data_mgmt.cu
+++ b/src/gromacs/mdlib/nbnxn_cuda/nbnxn_cuda_data_mgmt.cu
@@ -70,11 +70,15 @@
 
 static bool bUseCudaEventBlockingSync = false; /* makes the CPU thread block */
 
-/* This is a heuristically determined parameter for the Fermi architecture for
- * the minimum size of ci lists by multiplying this constant with the # of
- * multiprocessors on the current device.
+/* This is a heuristically determined parameter for the Fermi, Kepler
+ * and Maxwell architectures for the minimum size of ci lists by multiplying
+ * this constant with the # of multiprocessors on the current device.
+ * Since the maximum number of blocks per multiprocessor is 16, the ideal
+ * count for small systems is 32 or 48 blocks per multiprocessor. Because
+ * there is a bit of fluctuations in the generated block counts, we use
+ * a target of 44 instead of the ideal value of 48.
  */
-static unsigned int gpu_min_ci_balanced_factor = 40;
+static unsigned int gpu_min_ci_balanced_factor = 44;
 
 /* Functions from nbnxn_cuda.cu */
 extern void nbnxn_cuda_set_cacheconfig(gmx_device_info_t *devinfo);