+/* Like get_cycles, but make sure the CPU is synchronized. */
+static __always_inline cycles_t get_cycles_sync(void)
+{
+ unsigned long long ret;
+ unsigned eax;
+ /* Don't do an additional sync on CPUs where we know
+ RDTSC is already synchronous. */
+ alternative_io("cpuid", ASM_NOP2, X86_FEATURE_SYNC_RDTSC,
+ "=a" (eax), "0" (1) : "ebx","ecx","edx","memory");
+ rdtscll(ret);
+ return ret;
+}
+