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That's a fascinating video about how modern processors work, but I don't see here why it's critical for performance. If you built a CPU without speculation, ho
by ken 8y ago
That's a fascinating video about how modern processors work, but I don't see here why it's critical for performance. If you built a CPU without speculation, how bad would perf be? What other features could you still use? How much do common algorithms depend on speculation?
- pkaye 8y agoSuperscalar processors have a deep pipeline with many execution units and keep a lot of instructions in flight so a penalty of a misprediction or stall is significant. Every time it reaches a branch instruction that depends on a result which is not yet available it would need to speculate or stall. Most programs consist of small amounts of compute code followed by a branch that might depends on the results of that code.