LXR linux/arch/x86/kernel/trace

   1/*
   2 * X86 trace clocks
   3 */
   4#include <asm/trace_clock.h>
   5#include <asm/barrier.h>
   6#include <asm/msr.h>
   7
   8/*
   9 * trace_clock_x86_tsc(): A clock that is just the cycle counter.
  10 *
  11 * Unlike the other clocks, this is not in nanoseconds.
  12 */
  13u64 notrace trace_clock_x86_tsc(void)
  14{
  15        u64 ret;
  16
  17        rdtsc_barrier();
  18        rdtscll(ret);
  19
  20        return ret;
  21}
  22