08:23 <nsaenz> Hi all, in user-space, when reading CNTVCT_EL0 like this: "__asm__ __volatile__("isb; mrs %0, cntvct_el0" : "=r" (val))" am I right to assume I don't need a compiler barrier (i.e. "memory" asm clobber) given 'mrs' isn't considered as a memory access by the compiler?

09:48 <arnd> nsaenz: it depends on what you want to measure: if you add a memory blobber, you force the compiler to serialize all memory accesses around the timer read, which can be costly but is required if you are trying to time that memory access.

11:08 <nsaenz> arnd: Thanks, makes sense.