#ifndef _LINUX_TRACE_CLOCK_H
  #define _LINUX_TRACE_CLOCK_H
  
  /*
   * 3 trace clock variants, with differing scalability/precision
   * tradeoffs:
   *
   *  -   local: CPU-local trace clock
   *  -  medium: scalable global clock with some jitter
   *  -  global: globally monotonic, serialized clock
   */
  #include <linux/compiler.h>
  #include <linux/types.h>
  
  extern u64 notrace trace_clock_local(void);
  extern u64 notrace trace_clock(void);
  extern u64 notrace trace_clock_global(void);

  extern u64 notrace trace_clock_counter(void);

  
  #endif /* _LINUX_TRACE_CLOCK_H */