[bug report] iommu_dma_unmap_sg() is very slow then running IO from remote numa node

[John Garry]

On 09/07/2021 15:24, Ming Lei wrote:
>> associated compromises.
> Follows the log of 'perf report'
> 
> 1) good(run fio from cpus in the nvme's numa node)

Hi Ming,

If you're still interested in this issue, as an experiment only you can 
try my rebased patches here:

https://github.com/hisilicon/kernel-dev/commits/private-topic-smmu-5.14-cmdq-4

I think that you should see a significant performance boost.

Thanks
John

> 
> -   34.86%     1.73%  fio       [nvme]              [k] nvme_process_cq                                                      ▒
>     - 33.13% nvme_process_cq                                                                                                  ▒
>        - 32.93% nvme_pci_complete_rq                                                                                          ▒
>           - 24.92% nvme_unmap_data                                                                                            ▒
>              - 20.08% dma_unmap_sg_attrs                                                                                      ▒
>                 - 19.79% iommu_dma_unmap_sg                                                                                   ▒
>                    - 19.55% __iommu_dma_unmap                                                                                 ▒
>                       - 16.86% arm_smmu_iotlb_sync                                                                            ▒
>                          - 16.81% arm_smmu_tlb_inv_range_domain                                                               ▒
>                             - 14.73% __arm_smmu_tlb_inv_range                                                                 ▒
>                                  14.44% arm_smmu_cmdq_issue_cmdlist                                                           ▒
>                               0.89% __pi_memset                                                                               ▒
>                               0.75% arm_smmu_atc_inv_domain                                                                   ▒
>                       + 1.58% iommu_unmap_fast                                                                                ▒
>                       + 0.71% iommu_dma_free_iova                                                                             ▒
>              - 3.25% dma_unmap_page_attrs                                                                                     ▒
>                 - 3.21% iommu_dma_unmap_page                                                                                  ▒
>                    - 3.14% __iommu_dma_unmap_swiotlb                                                                          ▒
>                       - 2.86% __iommu_dma_unmap                                                                               ▒
>                          - 2.48% arm_smmu_iotlb_sync                                                                          ▒
>                             - 2.47% arm_smmu_tlb_inv_range_domain                                                             ▒
>                                - 2.19% __arm_smmu_tlb_inv_range                                                               ▒
>                                     2.16% arm_smmu_cmdq_issue_cmdlist                                                         ▒
>              + 1.34% mempool_free                                                                                             ▒
>           + 7.68% nvme_complete_rq                                                                                            ▒
>     + 1.73% _start
> 
> 
> 2) bad(run fio from cpus not in the nvme's numa node)
> -   49.25%     3.03%  fio       [nvme]              [k] nvme_process_cq                                                      ▒
>     - 46.22% nvme_process_cq                                                                                                  ▒
>        - 46.07% nvme_pci_complete_rq                                                                                          ▒
>           - 41.02% nvme_unmap_data                                                                                            ▒
>              - 34.92% dma_unmap_sg_attrs                                                                                      ▒
>                 - 34.75% iommu_dma_unmap_sg                                                                                   ▒
>                    - 34.58% __iommu_dma_unmap                                                                                 ▒
>                       - 33.04% arm_smmu_iotlb_sync                                                                            ▒
>                          - 33.00% arm_smmu_tlb_inv_range_domain                                                               ▒
>                             - 31.86% __arm_smmu_tlb_inv_range                                                                 ▒
>                                  31.71% arm_smmu_cmdq_issue_cmdlist                                                           ▒
>                       + 0.90% iommu_unmap_fast                                                                                ▒
>              - 5.17% dma_unmap_page_attrs                                                                                     ▒
>                 - 5.15% iommu_dma_unmap_page                                                                                  ▒
>                    - 5.12% __iommu_dma_unmap_swiotlb                                                                          ▒
>                       - 5.05% __iommu_dma_unmap                                                                               ▒
>                          - 4.86% arm_smmu_iotlb_sync                                                                          ▒
>                             - 4.85% arm_smmu_tlb_inv_range_domain                                                             ▒
>                                - 4.70% __arm_smmu_tlb_inv_range                                                               ▒
>                                     4.67% arm_smmu_cmdq_issue_cmdlist                                                         ▒
>              + 0.74% mempool_free                                                                                             ▒
>           + 4.83% nvme_complete_rq                                                                                            ▒
>     + 3.03% _start