add a basic DTrace distribution plot formatter

formatters/dtrace_agg

@@ -0,0 +1,79 @@
+#!/bin/ksh
+#
+# DTrace Distribution Formatter
+#
+#  This formatter reads and restructures periodic output from a DTrace
+#  script which is, itself, written to output a distribution plot from
+#  one of the *quantize() aggregation functions.
+#
+#  Below is a slight modification of a script by Brendan Gregg
+#  (iolatency.d) which prints the latency of all I/O operations
+#  once a second.  Note that it prints no other output, except for
+#  a "===" separator line after each second has passed.
+#
+#  Use it with heapmap in log-linear mode, like so:
+#
+#    ./iolatency.d | ./formatters/dtrace_agg | ./heatmap -L
+#
+#---------------------------------------------------------------------
+#   #!/usr/sbin/dtrace -qs
+#
+#   io:::start
+#   {
+#     start[arg0] = timestamp;
+#   }
+#
+#   io:::done
+#   /start[arg0]/
+#   {
+#     this->microseconds = (timestamp - start[arg0]) / 1000;
+#     time = llquantize(this->microseconds, 10, 2, 8, 100);
+#     start[arg0] = 0;
+#   }
+#
+#   tick-1s
+#   {
+#     printa("%@d\n", @time);
+#     printf("===\n");
+#     trunc(@time);
+#   }
+#---------------------------------------------------------------------
+#
+
+while read line; do
+  set -- $line
+
+  #
+  # End of Record:
+  #
+  if [[ $1 == "===" ]]; then
+    echo $record
+    record=
+    continue
+  fi
+
+  #
+  # Skip Header/Blank Rows:
+  #
+  if [[ $1 == "" || $3 == "Distribution" ]]; then
+    continue
+  fi
+
+  #
+  # Process a bucket row:
+  #
+  if [[ $1 == ">=" ]]; then
+    bkt=$2
+    count=$4
+  elif [[ $1 == "<" ]]; then
+    bkt=0
+    count=$4
+  else
+    bkt=$1
+    count=$3
+  fi
+
+  if (( count > 0 )); then
+    record="$record ${bkt}*${count} "
+  fi
+done