Abstract: A starvation avoidance mechanism for an input/output node of a computer system. A scheduler unit includes a first buffer circuit and a second buffer circuit. The first buffer circuit includes a first plurality of buffers for storing selected control commands received from a first source and the second buffer circuit includes a second plurality of buffers for storing selected control commands received from a second source. The scheduler further includes an arbitration circuit coupled to the first buffer circuit and to the second buffer circuit. The arbitration circuit may be configured to arbitrate between the control commands stored in the first buffer circuit and the control commands stored in the second buffer circuit. The outcome of selected arbitration cycles may be dependent upon a number of times in which a control command from a given one of the buffers is blocked due to an unavailable destination.

Abstract: A computer system I/O node. An input/output node for a computer system includes a first receiver unit configured to receive a first command on a first communication path and a first transmitter unit coupled to transmit a first corresponding command that corresponds to the first command on a second communication path. The input/output node also includes a second receiver unit configured to receive a second command on a third communication path and a second transmitter unit coupled to transmit a second corresponding command that corresponds to the second command on a fourth communication path. Further, the input/output node includes a bridge unit coupled to receive selected commands from the first receiver and the second receiver and configured to transmit commands corresponding to the selected commands upon a peripheral bus.

Abstract: A virtual channel buffer bypass in a computer system input/output node. A control unit of an input/output node for a computer system includes a buffer circuit configured to receive control commands. The buffer circuit may include a plurality of buffers each corresponding to a respective virtual channel of a plurality of virtual channels for storing selected control commands that belong to the respective virtual channel. The buffer circuit may also be configured to determine whether each of the plurality of buffers is empty prior to storing a particular control command corresponding to a given one of the plurality of buffers. In addition, the buffer circuit may be configured to cause the particular control command to bypass the given one of the plurality of buffers in response to determining that each of the plurality of buffers is empty.