On-demand multi-tiered hang buster for SMT microprocessor

A system, comprising:

• at least one processor;
• and
• a memory storing a program, which, when executed on the at least one processor, perform an operation for breaking out of a hang condition in the processor, the operation comprising:
• determining a first plurality of actions available at each of a plurality of tiers used for breaking out of the hang condition in the processor;
• after detecting the hang condition on a first thread of the processor, performing one or more actions available at a first tier of the plurality of tiers to break out of the hang condition;
• after performing the one or more actions at the first tier and determining that the hang condition is still present, performing one or more actions available at one or more second tiers of the plurality of tiers to break out of the hang condition;
• and
• upon reaching a last tier of the plurality of tiers after performing the one or more actions at the first tier and performing the one or more actions at the one or more second tiers:
• determining that the hang condition is still present;
• and
• performing a flush operation to break out of the hang condition, wherein the flush operation is one of the first plurality of actions and is performed at an initial time at the last tier of the plurality of tiers in order to break out of the hang condition.

A computer program product, the computer program product comprising:

• a computer-readable storage medium having computer-readable program code embodied therewith, the computer-readable program code executable by one or more computer processors to perform an operation for breaking out of a hang condition in a processing unit, the operation comprising:
• determining a first plurality of actions available at each of a plurality of tiers used for breaking out of the hang condition in the processing unit;
• after detecting the hang condition on a first thread of the processor, performing one or more actions available at a first tier of the plurality of tiers to break out of the hang condition;
• after performing the one or more actions at the first tier and determining that the hang condition is still present, performing one or more actions available at one or more second tiers of the plurality of tiers to break out of the hang condition;
• and
• upon reaching a last tier of the plurality of tiers after performing the one or more actions at the first tier and performing the one or more actions at the one or more second tiers:
• determining that the hang condition is still present;
• and
• performing a flush operation to break out of the hang condition, wherein the flush operation is one of the first plurality of actions and is performed at an initial time at the last tier of the plurality of tiers in order to break out of the hang condition.