Are you tired of your high-performance computing (HPC) workloads taking forever to complete?

To kick things off: why RHEL is such an excellent choice for your HPC needs. Unlike other operating systems, RHEL provides a stable and reliable platform that can handle even the most demanding workloads with ease. Plus, it comes packed with all sorts of goodies like kernel tuning options, memory management tools, and file system optimizations to help you get the best performance possible.

Now, Let’s roll with some tips for optimizing your HPC performance on RHEL 8:

1) Start by enabling the High-Performance Computing (HPC) kernel tunables. These settings are designed specifically for HPC workloads and can help improve CPU scheduling, memory management, and I/O performance. To enable these tunables, simply run this command:

# This script enables the High-Performance Computing (HPC) kernel tunables on RHEL 8.

# First, we need to use the "sudo" command to run the following command with root privileges.
sudo grubby --update-kernel=ALL --args="hugepagesz=2M rd.lvm.lvmetad.scan=0"

# The "grubby" command is used to manipulate GRUB2 configuration files. In this case, we are updating the kernel configuration for all kernels.

# The "--update-kernel=ALL" option specifies that we want to update the configuration for all kernels.

# The "--args" option allows us to add additional kernel arguments. In this case, we are adding two arguments: "hugepagesz=2M" and "rd.lvm.lvmetad.scan=0".

# The "hugepagesz=2M" argument sets the size of the huge pages to 2 megabytes. Huge pages are used for memory management and can improve performance for HPC workloads.

# The "rd.lvm.lvmetad.scan=0" argument disables the scanning of LVM metadata. This can improve I/O performance for HPC workloads.

# Overall, this command enables the HPC kernel tunables, which are specifically designed to improve performance for HPC workloads by optimizing CPU scheduling, memory management, and I/O performance.

This will add the necessary kernel parameters to your boot configuration and enable huge pages (which can significantly improve memory performance) as well as disable LVM metadata scanning during system startup (which can help reduce I/O overhead).

2) Next, file systems. RHEL 8 supports a variety of different file systems that are optimized for HPC workloads, including XFS and ext4 with the data=journal option. To choose the best file system for your needs, consider factors like I/O performance, metadata management, and scalability.

3) Speaking of I/O performance, RAID configurations. If you have multiple disks in a server, it’s worth considering setting up a RAID array to improve disk throughput and reduce data loss in the event of a failure. For HPC workloads, RAID 0 (striping) or RAID 10 (mirroring with striping) are typically good choices.

4) Now CPU scheduling. By default, Linux uses a round-robin scheduler that can result in poor performance for HPC workloads due to context switching overhead. To improve CPU utilization and reduce latency, consider using the Completely Fair Scheduler (CFS). This scheduler is designed specifically for HPC workloads and provides better fairness and scalability than other schedulers.

5) Finally, memory management. RHEL 8 supports a variety of different memory management options that can help improve performance for HPC workloads. For example, you can enable transparent huge pages (THP), which allow the kernel to allocate large contiguous blocks of memory directly from swap instead of using smaller chunks. This can significantly reduce I/O overhead and improve overall system performance.