detect rdtscp instruction at runtime

[teknoraver]

Signed-off-by: Matteo Croce mcroce@redhat.com

[paboldin]

Thanks! But get_access_time is inlined, so having a branch in it is not a very good idea. Probably, we can write a make-time check for rdtscp (like ./configure)? Another option for me was to change code on the fly, replacing all the rdtscps with rdtscs.

[teknoraver]

This looks better? RDTSCP detected at compile time by a shellscript and generated .h file with inline get_access_time()

[paboldin]

Let me check both of these and I will merge then.

[paboldin]

@teknoraver thanks!