What is the gcc cpu-type that includes support for RDTSCP?

Question

I am using RDTSCP to replace LFENCE;RDTSC sequences and also get the processor ID back so that I know when I'm comparing TSC values after the thread was rescheduled to another CPU.

To ensure I don't run RDTSCP on a too old machine I fallback to RDTSC after a CPUID check (using libcpuid). I'd like to try using the gcc multiple target attribute functionality instead of a CPUID call:

int core2_func (void) __attribute__ ((__target__ ("arch=core2")));

The gcc manual lists a number of cpu families (haswell, skylake, ...). How would I find which cpu family first introduced RDTSCP?

Answer 1

All AMD processors since the K8 Hammer support RDTSCP.

On Intel processors, RDTSCP is supported on Nehalem and later, Silvermont and later, and Knights Landing and later.