On Thu, May 30, 2024 at 10:36:57PM -0700, Chia-I Wu wrote: > We can skip children resources when the parent resource does not cover > the range. > > This should help vmf_insert_* users on x86, such as several DRM drivers. > On my AMD Ryzen 5 7520C, when streaming data from cpu memory into amdgpu > bo, the throughput goes from 5.1GB/s to 6.6GB/s. perf report says > > 34.69%--__do_fault > 34.60%--amdgpu_gem_fault > 34.00%--ttm_bo_vm_fault_reserved > 32.95%--vmf_insert_pfn_prot > 25.89%--track_pfn_insert > 24.35%--lookup_memtype > 21.77%--pat_pagerange_is_ram > 20.80%--walk_system_ram_range > 17.42%--find_next_iomem_res > > before this change, and > > 26.67%--__do_fault > 26.57%--amdgpu_gem_fault > 25.83%--ttm_bo_vm_fault_reserved > 24.40%--vmf_insert_pfn_prot > 14.30%--track_pfn_insert > 12.20%--lookup_memtype > 9.34%--pat_pagerange_is_ram > 8.22%--walk_system_ram_range > 5.09%--find_next_iomem_res > > after. Is there any documentation that explicitly says that the children resources must not overlap parent's one? Do we have some test cases? (Either way they needs to be added / expanded). P.S> I'm not so sure about this change. It needs a thoroughly testing, esp. in PCI case. Cc'ing to Ilpo. -- With Best Regards, Andy Shevchenko
