Crossbar switch with primary and secondary pickers

A computer processing system, comprising:

• a crossbar switch configured to route packets from source ports to destination ports;
• the crossbar switch including a crossbar switch command scheduler (command scheduler) configured to schedule at least two command packets per clock cycle;
• the command scheduler having a primary picker configured to select a command packet during the clock cycle;
• and
• the command scheduler having a secondary picker different from the primary picker, the secondary picker configured to select another command packet during the clock cycle,
• wherein the second picker is dependent on the first picker for source port selection from the source ports,
• wherein the primary picker selects from a first group of source ports and the secondary picker selects from a second group of source ports in the clock cycle,
• wherein the primary picker selects from the second group of source ports and the secondary picker selects from the first group of source ports in the next clock cycle, and
• wherein the secondary picker command packet selection is cancelled upon a destination port collision with the primary picker command packet selection.

A method of scheduling packets between source ports and destination ports connected through a crossbar switch of a processor, comprising:

• scheduling at least two command packets to be routed through the crossbar switch from the source ports to the destination ports during a clock cycle;
• picking a first command packet with a first picker to be routed through the crossbar switch during the clock cycle;
• and
• picking a second command packet with a second picker different from the first picker to be routed through the crossbar switch during the clock cycle,
• wherein the second picker is dependent on the first picker for source port selection from the source ports,
• wherein the first command packet is picked from a first group of source ports and the second command packet is picked from a second group of source ports in the clock cycle,
• wherein the first command packet is picked from the second group of source ports and the second command packet is picked from the first group of source ports in the next clock cycle, and
• wherein the second command packet is cancelled upon a destination port collision with the first command packet.

A non-transitory computer-readable storage medium containing a first set of instructions adapted to configure, in part, a processor, wherein the processor is configured to implement a second set of instructions, the second set of instructions comprising:

• a crossbar switch scheduler code segment for scheduling at least two packet commands per clock cycle;
• a first picker code segment for picking a command packet during the clock cycle;
• and
• a second picker code segment for picking another command packet during the clock cycle, the second picker code segment different from the first picker code segment,
• wherein the second picker is dependent on the first picker for source port selection,
• wherein the first picker code segment selects from a first group of source ports and the second picker code segment selects from a second group of source ports in the clock cycle,
• wherein the first picker code segment selects from the second group of source ports and the second picker code segment selects from the first group of source ports in the next clock cycle, and
• wherein the second picker code segment command packet selection is cancelled upon a destination port collision with the first picker code segment command packet selection.

A non-transitory computer readable media including hardware design code stored thereon, and when processed generates other intermediary data to create one or more mask works for a processor configured to perform a method of scheduling packets between source ports and destination ports through a crossbar switch, comprising:

• scheduling at least two command packets to be routed through the crossbar switch from the source ports to the destination ports during a clock cycle;
• picking a first command packet with a first picker to be routed through the crossbar switch during the clock cycle;
• and
• picking a second command packet with a second picker different from the first picker to be routed through the crossbar switch during the clock cycle,
• wherein the second picker is dependent on the first picker for source port selection from the source ports,
• wherein the first picker selects from a first group of source ports and the second picker selects from a second group of source ports in the clock cycle,
• wherein the first picker selects from the second group of source ports and the second picker selects from the first group of source ports in the next clock cycle, and
• wherein the second picker command packet selection is cancelled upon a destination port collision with the first picker command packet selection.