On 2022/4/18 15:00, Tian, Kevin wrote:
From: Lu Baolu<[email protected]>
Sent: Saturday, April 16, 2022 8:31 PM
PRQ overflow may cause I/O throughput congestion, resulting in unnecessary
degradation of IO performance. Appropriately increasing the length of PRQ
can greatly reduce the occurrence of PRQ overflow. The count of maximum
page requests that can be generated in parallel by a PCIe device is
statically defined in the Outstanding Page Request Capacity field of the
PCIe ATS configure space.
The new lenght of PRQ is calculated by summing up the value of Outstanding
Page Request Capacity register across all devices where Page Requests are
supported on the real PR-capable platfrom (Intel Sapphire Rapids). The
result is round to the nearest higher power of 2.
The actual requirement is usage and platform specific. What about
doubling the default size and also provide an option for admin to
tune?
I also have this in my list to provide an opt-in interface for user. But
I don't want to include it in this series as this is only for small
tuning. The opt-in interface looks more like a new feature. :-)
Best regards,
baolu
_______________________________________________
iommu mailing list
[email protected]
https://lists.linuxfoundation.org/mailman/listinfo/iommu
