Debugging instruction execution errors in a simulated computer system

A non-transitory computer-readable storage medium having instructions stored thereon for a simulated computer system that when executed by a computing system directs the computing system to:

• generate two separate simulations of a same system;
• cause a code comprising a set of instructions to execute on the two separate simulations;
• perform a trace operation starting from a start instruction to an end instruction;
• accumulate a first checksum value for each instruction executed in a first simulation of the two separate simulations;
• accumulate a second checksum value for each instruction executed in a second simulation of the two separate simulations;
• report at a reporting frequency, for each of the first simulation and the second simulation a partial total first checksum value of the accumulated first checksum value, a partial total second checksum value of the accumulated second checksum value respectively, and an instruction count;
• for each reported instruction count:
• compare the partial total first checksum value with the partial total second checksum value;
• in response to the comparison that the partial total first checksum value does not equal the partial total second checksum value:
• set the start instruction to the instruction count minus the reporting frequency and the end instruction to the instruction count, and
• when the end instruction is one greater than the start instruction, generate a notification of an instruction execution deviation that includes a final checksum report.

A computer implemented method, comprising:

• generating two separate simulations of a same system;
• causing a code comprising a set of instructions to execute on the two separate simulations;
• performing a trace operation starting from a start instruction to an end instruction of the set of instructions on the two separate simulations;
• during performing the trace operation, identifying an instruction execution deviation between the code executed in the two separate simulations by:
• comparing checksum values at a reporting frequency, which comprises accumulating a first checksum value for each instruction executed of a first simulation of the two separate simulations and accumulating a second checksum value for each instruction executed of a second simulation of the two separate simulations;
• determining that the comparison of the checksum values indicates a mismatch;
• and
• using instruction count and the reporting frequency to capture at least one instruction leading up to the instruction execution deviation;
• and
• reporting at the reporting frequency a partial total first checksum value of the accumulated first checksum value and the instruction count in a first checksum report and reporting at the reporting frequency a partial total second checksum value of the accumulated second checksum value and the instruction count in a second checksum report.