Scalable dependency matrix with multiple summary bits in an out-of-order processor

A system comprising:

• a dependency matrix in an issue queue of an out-of-order processor;
• a memory having computer readable instructions;
• and
• one or more processors for executing the computer readable instructions, the computer readable instructions controlling the one or more processors to perform operations comprising:
• tracking dependencies between instructions in an issue queue, wherein the tracking comprises for each instruction in the issue queue:
• identifying whether the instruction is dependent on each of a threshold number of instructions added to the issue queue prior to the instruction, wherein a dependency between the instruction and each of the threshold number of instructions is tracked individually;
• and
• identifying whether the instruction is dependent on one or more other instructions added to the issue queue prior to the instruction that are not included in the each of the threshold number of instructions, wherein a dependency between the instruction and each of the other instructions is tracked as a plurality of groups by indicating that a dependency exists between the instruction and one of the groups based on identifying a dependency between the instruction and at least one instruction in the group, wherein each of the other instructions is assigned to at least one of the groups;
• and
• issuing instructions from the issue queue based at least in part on the tracking.

A computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause the processor to perform operations comprising:

• tracking dependencies between instructions in an issue queue, wherein the tracking comprises for each instruction in the issue queue:
• identifying whether the instruction is dependent on each of a threshold number of instructions added to the issue queue prior to the instruction, wherein a dependency between the instruction and each of the threshold number of instructions is tracked individually;
• and
• identifying whether the instruction is dependent on one or more other instructions added to the issue queue prior to the instruction that are not included in the each of the threshold number of instructions, wherein a dependency between the instruction and each of the other instructions is tracked as a plurality of groups by indicating that a dependency exists between the instruction and one of the groups based on identifying a dependency between the instruction and at least one instruction in the group, wherein each of the other instructions is assigned to at least one of the groups;
• and
• issuing instructions from the issue queue based at least in part on the tracking.