Public bug reported: BugLink: https://bugs.launchpad.net/bugs/2169668
[ Impact ] PerfOpt is a feature in amd's IOMMU. This allows bypassing of IOMMU translation when a device sits on identity domain and is trying to access system memory. This allows 10-20% uplift in performance for iGPU designs like Strix Halo and Gorgon Halo. [ Fix ] Cherry-pick the following commits to the oem-7.3 kernel: - [PATCH 0/2] IOMMU Performance Optimization support[1] Which has landed in linux-next commit 6e87850d1a8f and e74db71a3530 respectively. One dependent patch is needed to cleanly apply then all: - iommu/amd: Refactor device probe and capability initialization This also has been included in linux-next commit 15d5b3027d9f. [ Test Plan ] Boot into the kernel with default boot options and check the following: 1. Look into the dmesg, and it should show "PerfOpt armed on IOMMU<N>", were 2. Run lspci -vvv and check amdgpu's capability registers. ATS, PRI, and PASID should be turned off. 3. Run basic graphic tests (glxgears, glxinfo) before and after suspend. It should function normally. [ Where problems could occur ] This feature is enabled only if the driver explicitly request it, so currently this impacts amdgpu on APU systems. amd_iommu_enable_perfopt() clears ATS, PRI, PASID and SVA for the device, and this now becomes default for amdgpu on If somehow there are features relying on these, they will get impacted. [ Additional information ] [1] https://lore.kernel.org/linux- iommu/[email protected]/ ** Affects: linux (Ubuntu) Importance: Undecided Status: New ** Description changed: - BugLink: + BugLink: https://bugs.launchpad.net/bugs/2169668 [ Impact ] PerfOpt is a feature in amd's IOMMU. This allows bypassing of IOMMU translation when a device sits on identity domain and is trying to access system memory. This allows 10-20% uplift in performance for iGPU designs like Strix Halo and Gorgon Halo. [ Fix ] - Cherry-pick the following commits: + Cherry-pick the following commits to the oem-7.3 kernel: - [PATCH 0/2] IOMMU Performance Optimization support[1] Which has landed in linux-next commit 6e87850d1a8f and e74db71a3530 respectively. One dependent patch is needed to cleanly apply then all: - iommu/amd: Refactor device probe and capability initialization This also has been included in linux-next commit 15d5b3027d9f. [ Test Plan ] Boot into the kernel with default boot options and check the following: - 1. Look into the dmesg, and it should show "PerfOpt armed on IOMMU<N>", were + 1. Look into the dmesg, and it should show "PerfOpt armed on IOMMU<N>", were 2. Run lspci -vvv and check amdgpu's capability registers. ATS, PRI, and PASID should be turned off. 3. Run basic graphic tests (glxgears, glxinfo) before and after suspend. It should function normally. - [ Where problems could occur ] This feature is enabled only if the driver explicitly request it, so currently this impacts amdgpu on APU systems. amd_iommu_enable_perfopt() clears ATS, PRI, PASID and SVA for the device, and this now becomes default for amdgpu on If somehow there are features relying on these, they will get impacted. - [ Additional information ] [1] https://lore.kernel.org/linux- iommu/[email protected]/ -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2169668 Title: [SRU] Enable IOMMU Performance Optimization support To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2169668/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
