AMD PerfOpt To Deliver New Performance Optimization For AMD iGPUs With Linux 7.4

Those using AMD integrated graphics on Linux such as the beefy Ryzen AI Max+ Strix Halo and Gorgon Halo hardware will be able to enjoy even better performance with the upcoming Linux 7.4 kernel.

AMD Ryzen AI Max already delivers stellar CPU and iGPU performance on Linux. Truly one of the best products ever and I continue to be impressed by it more than one year later of relentless benchmarking of the hardware I have available. Now all the more exciting, a new performance optimization is inbound with the upcoming Linux 7.4 kernel. It's not Ryzen AI Max specific either but can benefit AMD iGPUs at large, just obviously with the likes of the Ryzen AI Max is more performance potential on the table especially in today's AI/LLM focused world.

This new optimization is PerfOpt... short for performance optimization. AMD IOMMU Performance Optimization is part of the AMD I/O Virtualization Technology (IOMMU) specification and described in the Linux kernel patches as:

"This feature allows privileged integrated I/O devices (GPUs) to bypass the IOMMU when directly accessing system memory. The IOMMU only enforces the IR/IW permission bits without GPA->SPA translations.

Drivers will opt into this behavior, and enable amdgpu to turn this feature on when an integrated GPU is already in identity mode. If a user prefers to keep it always off (even with identity mode) there is also a module parameter to force it off."

AMD PerfOpt will be enabled by default for AMD iGPUs with Linux 7.4 to bypass the IOMMU when directly accessing system memory. In turn this should yield an overhead reduction and nice performance boost.

The amdgpu.iommu_perfopt module parameter will allow toggling the feature if wanting to disable it for AMD iGPUs. This feature is intended only for integrated I/O devices and not discrete GPUs or other external hardware. You can look for "PerfOpt" in your kernel dmesg to verify if it's enabled.

Those interested in this AMD PerfOpt feature set to be merged for the Linux 7.4 kernel by way of the IOMMU tree can find the patches on the kernel mailing list.

Update: Benchmarks! AMD Boosting AI/LLM Performance For Radeon iGPUs As Much As 18~23% With Linux 7.4