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by keith_analog
729 days ago
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There's a fairly recent study looking into the cost of raising an interrupt. TLDR: the cost on conventional systems is quite high; a significant part of the cost can be eliminated by using a custom kernel; even with a custom kernel, there remains a substantial cost. https://par.nsf.gov/servlets/purl/10079614 To my knowledge, the remaining cost could be decreased to approximately the same cost as a branch mispredict, but getting there would require changes to the chip hardware and software stack. |
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Do it even need to be a misprediction?
If you are completely focused on latency then flushing everything else makes sense. But I would think that if you continue execution for now and put a branch instruction into the queue you'd reduce the cost per interrupt even further.