There has been great revolution in server industry in terms of inventions of PCIe SR_IOV and MR_IOV. Server industry went through transformation due to an invention of SR_IOV. SR_IOV has introduced the concept of virtual functions which can be utilized in servers. The main issue was increasing the number of physical functions for servers. Servers needed large number of functions on PCIe device which was not possible to implement. That caused the great invention of virtual functions in PCIe.
Every virtual function can be assigned to one of system image which can directly communicate with that system image. That makes the communication faster between system image and virtual function. Virtual function helps in terms of generating resources dynamically and assigning it to system image. This great concept has helped server to use PCIe with as many numbers of cores on server system. This advancement has made PCIe number 1 choice to be used in servers.
Another aspect which makes SR_IOV useful in server is its ease of implementation. It requires an implementation of simple configuration space which can be used to create the virtual functions. Configuration space can be simple to implement and based on which virtual functions can be created. This dynamic concept of creating the virtual function helps reducing the required resources on PCIe device and adding the flexibility to use it for any number of cores. This is the reason PCIe SR_IOV based virtualization has increased the demand of PCIe in servers.
Another great advancement which has brought the revolution in server is PCIe MR_IOV. While, SR_IOV was targeted for single root complex, MR_IOV was targeted for multiple root complex. MR_IOV platforms can support upto 160 endpoints in different virtual hierarchy. MR_IOV has brought the virtualization to new heights. MR_IOV endpoint supports the base function which can be configured to implement multiple virtual hierarchies. Multiple virtual hierarchies allow large numbers of endpoints including SR and MR to be existing on platform. MR_IOV has allowed huge number of function availability on platforms through virtualization. Due to virtualization, PCIe based MR_IOV and SR_IOV has become first choice of usage in servers. It is great transformation to use these advancements in servers.
