Wei Huang via Lsf-pc wrote: > Hi All, > > I want to proposal a talk for the LSFMMBPF conference: Enabling Smart > Data Stream Accelerator (SDXI) Support for Linux. > > The smart data stream accelerator (SDXI) is an industry standard [1] > that provides various advanced capabilities, such as offloading DMA > operations, supporting user-space addresses, and offering other advanced > data processing features. With the integration of SDXI into a SoC, DMA > offloading can now be supported across different address spaces. This > talk focuses on a software design which enables comprehensive SDXI > support across multiple software layers in the Linux Kernel. These > interfaces not only facilitate SDXI hardware management but also allow > kernel space subsystems and user space applications to directly own and > control SDXI hardware under the protection of IOMMU. > > To illustrate the practical applications of SDXI, Red Hat and AMD > developed a user-space library that leverages the SDXI driver interface, > demonstrating various use cases, such as memory operation offloading, in > both bare-metal and virtual environments. > > The prototype device driver [2] and user-space library are available for > testing. We continue to work on the improvement of both components and > plan to upstream the device driver soon. > > == DISCUSSION == > At this conference, we plan to discuss with the community on: > > 1) Use Cases > * Linux DMA engine Is this a use case? In other words copy-offload engines have struggled for more than a decard to impact kernel use cases due to the maintenance burden of split async / synchronous paths for kernel-buffer-to-kernel-buffer copies. The Linux dmaengine subsystem mainly stayed relevant due to device-DMA use cases. > * Kernel task offloading (e.g., bulk copying) > * QoS and kernel perf integration > * New use cases I think for this effort to be successful it needs to focus on one embarassingly clear use case where CPU copy hits a scaling wall, not a gallery of potential use cases. > 2) User-Space API Interface > * IOCTL proposal > * Security control > * User-space app integration The best API for copy-offload is no new API, i.e. transparent acceleration of existing software. For example, io_uring is already asking applications to rewrite and submit bulk work to the kernel. It would be lovely if the applications got copy offload for free after paying the io_uring conversion cost.
