[Interpreter] Add visualization tool for Ignition dispatch counters.

tools/ignition/bytecode_dispatches_report.py

Index: tools/ignition/bytecode_dispatches_report.py
diff --git a/tools/ignition/bytecode_dispatches_report.py b/tools/ignition/bytecode_dispatches_report.py
new file mode 100755
index 0000000000000000000000000000000000000000..7a8ebf856afddb1afffc9e471373b7beb08856aa
--- /dev/null
+++ b/tools/ignition/bytecode_dispatches_report.py
@@ -0,0 +1,188 @@
+#! /usr/bin/python
+#
+# Copyright 2016 the V8 project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+#
+
+import argparse
+import heapq
+import json
+from matplotlib import colors
+from matplotlib import pyplot
+import numpy
+import struct
+
+
+__DESCRIPTION = """
+Process v8.ignition_dispatches_counters.json and list top counters,
+or plot a dispatch heatmap.
+"""
+
+
+__HELP_EPILOGUE = """
+examples:
+  # Print the top 10 counters (default mode), reading from default
+  # filename v8.ignition_dispatches_counters.json
+  $ tools/ignition/bytecode_dispatches_report.py
+
+  # Print the top 15 counters reading from data.json
+  $ tools/ignition/bytecode_dispatches_report.py -t 15 data.json
+
+  # Do not print the top counters and save to default filename
+  # v8.ignition_dispatches_counters.svg
+  $ tools/ignition/bytecode_dispatches_report.py -t 0 -p -o data.svg

[rmcilroy, 2016/04/12 14:08:51]

Please update this example if you take the comment below of printing of the top
X if --plot is not set.

[Stefano Sanfilippo, 2016/04/12 14:26:26]

Done.

+
+  # Print the top 10 counters and save a heatmap to data.svg
+  $ tools/ignition/bytecode_dispatches_report.py -p -o data.svg
+
+  # Open the heatmap in an interactive viewer
+  $ tools/ignition/bytecode_dispatches_report.py -p -i
+"""
+
+__COUNTER_BITS = struct.calcsize("P") * 8  # Size in bits of a pointer
+
+
+__COUNTER_MAX = 2**__COUNTER_BITS - 1

[rmcilroy, 2016/04/12 14:08:51]

nit - remove newlines between __COUNTER_BITS and __COUNTER_MAX

[Stefano Sanfilippo, 2016/04/12 14:26:26]

Done.

+
+
+def warn_if_counter_may_have_saturated(dispatches_table):
+  for source, counters_from_source in dispatches_table.items():
+    for destination, counter in counters_from_source.items():
+      if counter == __COUNTER_MAX:
+        print "WARNING: {} -> {} may have saturated.".format(source,
+                                                             destination)
+
+
+def print_top_counters(dispatches_table, top_number):
+  flattened_counters = {}
+  for source, counters_from_source in dispatches_table.items():
+    for destination, counter in counters_from_source.items():
+      flattened_counters[source, destination] = counter
+
+  top_counters = heapq.nlargest(top_number, flattened_counters.items(),
+                                key=lambda x: x[1])
+
+  print "Top {} dispatch counters:".format(top_number)
+  for source_destination_pair, counter in top_counters:
+    print "{:>12d}\t{}".format(counter, " -> ".join(source_destination_pair))
+
+
+def plot_dispatches_table(dispatches_table, figure, axis):
+  labels = sorted(dispatches_table.keys())
+
+  counters_matrix = numpy.empty([len(labels), len(labels)], dtype=int)
+  for from_index, from_name in enumerate(labels):
+    current_row = dispatches_table[from_name];
+    for to_index, to_name in enumerate(labels):
+      counters_matrix[from_index, to_index] = current_row.get(to_name, 0)
+
+  # Reverse y axis for a nicer appeareance

[rmcilroy, 2016/04/12 14:08:51]

appearance

[Stefano Sanfilippo, 2016/04/12 14:26:26]

Done.

+  xlabels = labels
+  ylabels = list(reversed(xlabels))
+  counters_matrix = numpy.flipud(counters_matrix)
+
+  image = axis.pcolor(
+    counters_matrix,
+    cmap='jet',
+    norm=colors.LogNorm(),
+    edgecolor='grey',
+    linestyle='dotted',
+    linewidth=0.5
+  )
+
+  axis.xaxis.set(
+    ticks=numpy.arange(0.5, len(xlabels)),
+    label="From bytecode handler"
+  )
+  axis.xaxis.tick_top()
+  axis.set_xlim(0, len(xlabels))
+  axis.set_xticklabels(xlabels, rotation='vertical')
+
+  axis.yaxis.set(
+    ticks=numpy.arange(0.5, len(ylabels)),
+    label="To bytecode handler",
+    ticklabels=ylabels
+  )
+  axis.set_ylim(0, len(ylabels))
+
+  figure.colorbar(
+    image,
+    ax=axis,
+    fraction=0.01,
+    pad=0.01
+  )
+
+
+def parse_command_line():
+  command_line_parser = argparse.ArgumentParser(
+    formatter_class=argparse.RawDescriptionHelpFormatter,
+    description=__DESCRIPTION,
+    epilog=__HELP_EPILOGUE
+  )
+  command_line_parser.add_argument(
+    "--plot_size", "-s",
+    metavar="N",
+    default=30,
+    help="shorter side, in inches, of the output plot (default 30)"
+  )
+  command_line_parser.add_argument(
+    "--plot", "-p",
+    action="store_true",
+    help="plot dispatches table heatmap"
+  )
+  command_line_parser.add_argument(
+    "--interactive", "-i",
+    action="store_true",
+    help="open an interactive viewer, rather than writing to file"
+  )
+  command_line_parser.add_argument(
+    "--print_top", "-t",

[rmcilroy, 2016/04/12 14:08:51]

name "top_count"

[Stefano Sanfilippo, 2016/04/12 14:26:26]

Done.

+    metavar="N",
+    type=int,
+    default=10,
+    help="print the top N counters (default 10)"
+  )
+  command_line_parser.add_argument(
+    "--output_filename", "-o",
+    metavar="<output filename>",
+    default="v8.ignition_dispatches_table.svg",
+    help=("file to save the plot file to. File type is deduced from the "
+          "extension. PDF, SVG, PNG supported")
+  )
+  command_line_parser.add_argument(
+    "input_filename",
+    metavar="<input filename>",
+    default="v8.ignition_dispatches_table.json",
+    nargs='?',
+    help="Ignition counters JSON file"
+  )
+
+  return command_line_parser.parse_args()
+
+
+def main():
+  program_options = parse_command_line()
+
+  with open(program_options.input_filename) as stream:
+    dispatches_table = json.load(stream)
+
+  warn_if_counter_may_have_saturated(dispatches_table)
+
+  if program_options.print_top > 0:

[rmcilroy, 2016/04/12 14:08:51]

This is default 10, so the only way to avoid it is to explicitly set it to '0'. 
How about we only either print the top X or do the plot (i.e., only do plot if
the --plot flag is set).

[Stefano Sanfilippo, 2016/04/12 14:26:26]

Done.

+    print_top_counters(dispatches_table, program_options.print_top)
+
+  if program_options.plot:
+    figure, axis = pyplot.subplots()
+    plot_dispatches_table(dispatches_table, figure, axis)
+
+    if program_options.interactive:
+      pyplot.show()
+    else:
+      figure.set_size_inches(program_options.plot_size,
+                             program_options.plot_size)
+      pyplot.savefig(program_options.output_filename)
+
+
+if __name__ == "__main__":
+  main()