Re: [RFC v2 00/11] Add dmabuf read/write via io_uring

[Pavel Begunkov <asml.silence@gmail.com>]

On 11/24/25 13:35, Anuj gupta wrote:
> This series significantly reduces the IOMMU/DMA overhead for I/O,
> particularly when the IOMMU is configured in STRICT or LAZY mode. I
> modified t/io_uring in fio to exercise this path and tested with an
> Intel Optane device. On my setup, I see the following improvement:
> 
> - STRICT: before = 570 KIOPS, after = 5.01 MIOPS
> - LAZY: before = 1.93 MIOPS, after = 5.01 MIOPS
> - PASSTHROUGH: before = 5.01 MIOPS, after = 5.01 MIOPS
> 
> The STRICT/LAZY numbers clearly show the benefit of avoiding per-I/O
> dma_map/dma_unmap and reusing the pre-mapped DMA addresses.

Thanks for giving it a run. Looks indeed promising, and I believe
that was the main use case Keith was pursuing. I'll fix up the
build problems for v3

-- 
Pavel Begunkov