message: Add per_cpu stats comments
diff: @@ -4,11 +4,33 @@ CMD="trace-cmd stat"
  echo $CMD
  $CMD
  +#
  +# cat /sys/kernel/tracing/per_cpu/cpu0/stats
  +# entries: 5
  +# overrun: 0
  +# commit overrun: 0
  +# bytes: 224
  +# oldest event ts: 96955.082688
  +# now ts: 97157.747457
  +# dropped events: 0
  +# read events: 0
  +#
  +# Ring buffer stats:
  +# Entries: The number of events that are still in the buffer.
  +# Overrun: The number of lost events due to overwriting when the buffer was full.
  +# Commit overrun: Should always be zero.
  +# This gets set if so many events happened within a nested event (ring buffer is re-entrant),
  +# that it fills the buffer and starts dropping events.
  +# Bytes: Bytes actually read (not overwritten).
  +# Oldest event ts: The oldest timestamp in the buffer.
  +# Now ts: The current timestamp.
  +# Dropped events: Events lost due to overwrite option being off.
  +# Read events: The number of events read.
  +#
  if [ -r "/sys/kernel/tracing/per_cpu/cpu0/stats" ]; then
  STAT_FILES=()
  -# /sys/kernel/tracing/per_cpu/cpu0/stats
  for (( i = 0 ; i <= 256 ; i++ )) ; do
  FILE="/sys/kernel/tracing/per_cpu/cpu${i}/stats"
  if [ ! -r ${FILE} ]; then
  