3 ms·

I can't find any evidence that RDTSCP is microcoded. That would defeat the whole purpose of a high-performance counter. Any source?

• vardump 7y ago
  I can't find any primary source, but I'm pretty sure about it.
• PeCaN 7y ago
  Agner Fog's instruction tables list it as issuing ~23 fused uops (a bit more or fewer depending on generation) and a throughput of 1 per ~32 cycles. That seems like it could be microcoded.