Fast & Scalable I/O for Emulated HPUX

HPE has positioned containerized solution called c-UX (code named Kiran) which runs HPUX in emulated (Itanium hardware emulation on x86) mode as a futuristic solution for the margin rich UNIX business. The value of containerized HPUX is that it allows customers using legacy HPUX applications to continue running on x86 hardware. Significant effort has been expended to increase the effectiveness of hardware resource utilization on c-UX. The next step in fully optimizing I/O in c-UX environment is to provide truly scalable high-performance, by enabling a single I/O device to provide DMA for multiple VMs. This scalability challenge can be solved using Single Root I/O Virtualization (SR-IOV) technology, delivering near-native I/O performance for multiple c-UX instances, while also providing memory and traffic isolation for security and high availability, accelerating live migrations, and reducing the cost and complexity of I/O solutions. Network and Storage adapters from various vendors can be used to realize SR-IOV on c-UX, which otherwise was not possible on native HPUX due to hardware and firmware limitations. This paper talks about an innovative mechanism to enable SR-IOV on emulated HPUX OS using Virtual Function I/O framework (VFIO) available in Linux. Disclosed is an approach of achieving highly scalable performance in c-UX application by allowing the guest OS direct access to parts of the I/O subsystem of the host and handle various aspects of the communication like DMA and interrupts. It also throws light on the network I/O performance gains achieved using this method