CAPI

Over a dozen special-purpose accelerators compatible with next-generation OpenPOWER servers that feature the Coherent Accelerator Processor Interface (CAPI) were revealed at the OpenPOWER Summit last week. These accelerators aim to help encourage the use of OpenPOWER based machines for technical and high-performance computing. Most of the accelerators are based on Xilinx high-performance FPGAs, but some feature custom silicon. IBM’s CAPI port is a PCIe 3.0-based interconnection specifically designed for programmable processors (e.g., ASICs, GPUs, FPGAs, etc.) that enables them to address the same memory address space as the CPU. CAPI requires custom hardware incorporated into IBM’s POWER8 processors, which is called the coherent accelerator processor proxy (CAPP), as well as a POWER service layer (PSL) integrated into CAPI-supporting processors. CAPP maintains a directory of cache...