On 09/06/2022 18:18, Bart Van Assche wrote:
SCSI host bus adapters that support 64-bit DMA may support much
larger transfer sizes than 128 KiB.
Indeed, and that is my problem today, as my storage controller is
generating DMA mapping lengths which exceeds 128K and they slow
everything down.
If you say that SRP enjoys best peformance with larger transfers then
can you please test this with an IOMMU enabled (iommu group type DMA
or DMA-FQ)?
Hmm ... what exactly do you want me to test? Do you perhaps want me to
measure how much performance drops with an IOMMU enabled?
Yes, I would like to know of any performance change with an IOMMU
enabled and then with an IOMMU enabled and including my series.
I don't have
access anymore to the SRP setup I referred to in my previous email. But
I do have access to devices that boot from UFS storage. For these
devices we need to transfer 2 MiB per request to achieve full bandwidth.
ok, but do you have a system where the UFS host controller is behind an
IOMMU? I had the impression that UFS controllers would be mostly found
in embedded systems and IOMMUs are not as common on there.
Thanks,
John
