#!/usr/bin/env stap
# alias_suffixes.stp
# Uses alias suffixes to track time intervals for a subset of kernel
# functions. Based on func_time_stats.stp.

global start, intervals

# We can apply a suffix to multiple probe points designated by one alias:
probe miscellany = syscall.{open,close,read,write} { }

probe miscellany {
      start[name, tid()] = gettimeofday_us()
}

# The 'return' suffix is passed on to each of the underlying probe points:
probe miscellany.return {
      t = gettimeofday_us(); old_t = start[name, tid()]
      if (old_t) intervals[name] <<< t - old_t
      delete start[name, tid()]
}

probe begin {
      printf("Collecting data... press Ctrl-C to stop.\n")
}

probe end {
      foreach (name in intervals) {
              printf("intervals for %s -- min:%dus avg:%dus max:%dus count:%d variance:%d\n",
                     name, @min(intervals[name]), @avg(intervals[name]),
                     @max(intervals[name]), @count(intervals[name]), @variance(intervals[name], 3))
              print(@hist_log(intervals[name]))
      }
}