"计算机指令系统" can be translated into English as "computer instruction set" or "instruction set architecture (ISA)".
"Computer instruction set" is a straightforward and commonly used term that directly refers to the set of instructions that a computer's processor can execute.
"Instruction set architecture (ISA)" is a more technical and precise term, often used in computer science and engineering contexts. It not only includes the set of instructions but also the way these instructions are encoded, the registers available, and the overall organization of the instruction set.
In most general contexts, "computer instruction set" would be sufficient. However, if you are discussing technical details or writing for a more specialized audience, "instruction set architecture (ISA)" might be more appropriate.