# Windows¶

## Prerequisites¶

• Microsoft MPI v10.0

## Workflow¶

• M-Star Build

• M-Star Solver

• M-Star Post

## Multi-GPU Setup¶

Requirements:

• GPU itself must support TCC mode (generally limited to Quadro and Tesla products)

• TCC mode set on GPUs participating in the simulation

• Monitor must not be connected to any TCC mode GPU

• MS-MPI is installed

When using multiple GPUs to run M-Star, each GPU participating in the simulation must be in “TCC Mode”. TCC mode disables the graphics capability of the GPU, putting the GPU into a mode where only CUDA calculations may take place. This means that you may not connect the monitor to any GPU that is in GPU mode. Therefore, when using multiple GPUs for M-Star on windows, you will need an auxiliary GPU dedicated for running the desktop environment.

Fig. 1 This is an example of a good multi-GPU setup on Windows

In the figure above, GPUs 1 and 2 would be setup in TCC mode and used for M-Star simulations. GPU 3 would be dedicated for desktop display purposes and left in the default WDDM mode.

To set the GPUs in TCC mode, open a command window in Administrator mode. Then identify where the “nvidia-smi” utility is installed. It is typically located at one of the following locations

• "C:\Program Files\NVIDIA Corporation\NVSMI\nvidia-smi"

• "C:\Windows\System32\nvidia-smi"

1. In the command window enter (note the quotes around the path). This shows all the GPUs in your machine. Take note of the GPUs you want to set in TCC mode.

"C:\Program Files\NVIDIA Corporation\NVSMI\nvidia-smi" -L

2. Then for each GPU you want to place in TCC mode, enter the following. Replace ID_HERE with the index from the previous step

"C:\Program Files\NVIDIA Corporation\NVSMI\nvidia-smi" -g ID_HERE -dm 1


The -dm 1 argument sets the GPU in TCC mode. The -g 0 argument selects GPU index 0 from step (1). Use the argument -dm 0 to place a GPU back into the default WDDM mode.

1. Reboot the computer

2. Open the command window again (cmd.exe) and run the following to verify. Ensure the configured GPUs show as being in TCC mode:

"C:\Program Files\NVIDIA Corporation\NVSMI\nvidia-smi" --query-gpu=index,name,driver_model.current --format=csv