# BabelSTREAM 

Follow this procedure to run BabelSTREAM and measure GPU memory bandwidth.

- Operating system: Ubuntu* 22.04
- Hardware: Intel® Data Center Max GPUs
- Software: Intel® oneAPI Base toolkit, Intel® oneAPI HPC toolkit
- Time to complete: 15 minutes 

<!-- BROKEN LINK For more information on BabelSTREAM, see https://github.com/UoB-HPC/BabelStream -->

1. Check whether the driver stack is installed.

   ```(bash)
   $ xpu-smi discovery
   ```

   The command should return at least one Intel® Data Center GPU Max device.

2. Check whether the oneAPI toolkit is installed.

   ```(bash)
   $ apt list intel-basekit intel-hpckit
   ```
   
   Expected output:
   ```(bash)
   Listing... Done
   intel-basekit/all,now 2023.2.0-49384 amd64 [installed]
   intel-hpckit/all,now 2023.2.0-49438 amd64 [installed]
   ```

3. If you previously have not configured your environment, install the Ubuntu 22.04 graphics driver.  See [dgpu-docs](https://dgpu-docs.intel.com/) for details.

   ```{note} Access to Ubuntu repositories, such as https://repositories.intel.com and https://apt.repos.intel.com, is required for installation. If proxy settings involve changes to environment variables such as http_proxy or https_proxy, small modifications are required in the following steps, such as adding -E (preserve environment) to sudo commands.
   ```
   
4. If you previously have not configured your environment, enable access to the Intel repo serving the oneAPI packages and install the oneAPI Base toolkit and HPC toolkit for Ubuntu 22.04.

   ```bash
   wget -O- https://apt.repos.intel.com/intel-gpg-keys/GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB \ | gpg --dearmor | sudo tee /usr/share/keyrings/oneapi-archive-keyring.gpg > /dev/null
   echo "deb [signed-by=/usr/share/keyrings/oneapi-archive-keyring.gpg] https://apt.repos.intel.com/oneapi all main" | sudo  tee /etc/apt/sources.list.d/oneAPI.list
   sudo apt update
   ```
   
   ```bash
   sudo apt install -y intel-basekit intel-hpckit
   ```

5. Install build dependencies.

   ```(bash)
   sudo apt install -y git build-essential cmake
   ```
   
6. Build BabelSTREAM.

   ```(bash)
   git clone https://github.com/UoB-HPC/BabelStream
   cd BabelStream
   source /opt/intel/oneapi/setvars.sh
   mkdir build && cd build
   cmake .. -DMODEL=sycl2020-acc -DSYCL_COMPILER=ONEAPI-ICPX
   make
   ```

7. Identify the number of GPUs presented in the system and their IDs.

   ```(bash)
   clinfo -l 
   
   Platform #0: Intel(R) OpenCL Graphics 
    +-- Device #0: Intel(R) Data Center GPU Max 1550 
     -- Device #1: Intel(R) Data Center GPU Max 1550 
   ```
   
   A device 0 should be available on any system with an Intel GPU with a GPU stack correctly installed, such as in this example:
   
   ```(bash)
   ONEAPI_DEVICE_SELECTOR=level_zero:0 ./sycl2020-acc-stream -s 134217728
   ```
   
   If additional devices are available, they can be selected by device number, as in the following example for a device number 1.
   
   ```(bash)
   ONEAPI_DEVICE_SELECTOR=level_zero:1 ./sycl2020-acc-stream -s 134217728
   ```

The following result snapshot is from Intel® Data Center GPU Max 1550:

```bash
BabelStream
Version: 5.0
Implementation: SYCL2020 accessors
Running kernels 100 times
Precision: double
Array size: 1073.7 MB (=1.1 GB)
Total size: 3221.2 MB (=3.2 GB)
Using SYCL device Intel(R) Data Center GPU Max 1550
Driver: 1.3.26516
...
```