[libc++] Support comparison of more than two data sets in compare-benchmarks

Author: ldionne

libcxx/utils/compare-benchmarks

@@ -1,6 +1,7 @@
 #!/usr/bin/env python3
 
 import argparse
+import functools
 import pathlib
 import re
 import statistics
@@ -62,35 +63,35 @@ def plain_text_comparison(data, metric, baseline_name=None, candidate_name=None)
  """
  Create a tabulated comparison of the baseline and the candidate for the given metric.
  """
+ # Compute additional info in new columns. In text mode, we can assume that we are
+ # comparing exactly two data sets (suffixed _0 and _1).
+ data['difference'] = data[f'{metric}_1'] - data[f'{metric}_0']
+ data['percent'] = 100 * (data['difference'] / data[f'{metric}_0'])
+
  data = data.replace(numpy.nan, None).sort_values(by='benchmark') # avoid NaNs in tabulate output
  headers = ['Benchmark', baseline_name, candidate_name, 'Difference', '% Difference']
  fmt = (None, '.2f', '.2f', '.2f', '.2f')
- table = data[['benchmark', f'{metric}_baseline', f'{metric}_candidate', 'difference', 'percent']].set_index('benchmark')
+ table = data[['benchmark', f'{metric}_0', f'{metric}_1', 'difference', 'percent']].set_index('benchmark')
  return tabulate.tabulate(table, headers=headers, floatfmt=fmt, numalign='right')
 
-def create_chart(data, metric, subtitle=None, baseline_name=None, candidate_name=None):
+def create_chart(data, metric, subtitle=None, series_names=None):
  """
- Create a bar chart comparing the given metric between the baseline and the candidate.
+ Create a bar chart comparing the given metric across the provided series.
  """
- data = data.sort_values(by='benchmark').rename(columns={
- f'{metric}_baseline': baseline_name,
- f'{metric}_candidate': candidate_name
- })
- figure = plotly.express.bar(data, title=f'{baseline_name} vs {candidate_name}',
- subtitle=subtitle,
- x='benchmark', y=[baseline_name, candidate_name], barmode='group')
+ data = data.sort_values(by='benchmark').rename(columns={f'{metric}_{i}': series_names[i] for i in range(len(series_names))})
+ title = ' vs '.join(series_names)
+ figure = plotly.express.bar(data, title=title, subtitle=subtitle, x='benchmark', y=series_names, barmode='group')
  figure.update_layout(xaxis_title='', yaxis_title='', legend_title='')
  return figure
 
 def main(argv):
  parser = argparse.ArgumentParser(
  prog='compare-benchmarks',
- description='Compare the results of two sets of benchmarks in LNT format.',
+ description='Compare the results of multiple sets of benchmarks in LNT format.',
  epilog='This script depends on the modules listed in `libcxx/utils/requirements.txt`.')
- parser.add_argument('baseline', type=argparse.FileType('r'),
- help='Path to a LNT format file containing the benchmark results for the baseline.')
- parser.add_argument('candidate', type=argparse.FileType('r'),
- help='Path to a LNT format file containing the benchmark results for the candidate.')
+ parser.add_argument('files', type=argparse.FileType('r'), nargs='+',
+ help='Path to LNT format files containing the benchmark results to compare. In the text format, '
+ 'exactly two files must be compared.')
  parser.add_argument('--output', '-o', type=pathlib.Path, required=False,
  help='Path of a file where to output the resulting comparison. If the output format is `text`, '
  'default to stdout. If the output format is `chart`, default to a temporary file which is '
@@ -107,43 +108,52 @@ def main(argv):
  parser.add_argument('--open', action='store_true',
  help='Whether to automatically open the generated HTML file when finished. This option only makes sense '
  'when the output format is `chart`.')
- parser.add_argument('--baseline-name', type=str, default='Baseline',
- help='Optional name to use for the "baseline" label.')
- parser.add_argument('--candidate-name', type=str, default='Candidate',
- help='Optional name to use for the "candidate" label.')
+ parser.add_argument('--series-names', type=str, required=False,
+ help='Optional comma-delimited list of names to use for the various series. By default, we use '
+ 'Baseline and Candidate for two input files, and CandidateN for subsequent inputs.')
  parser.add_argument('--subtitle', type=str, required=False,
  help='Optional subtitle to use for the chart. This can be used to help identify the contents of the chart. '
  'This option cannot be used with the plain text output.')
  args = parser.parse_args(argv)
 
- if args.format == 'text' and args.subtitle is not None:
- parser.error('Passing --subtitle makes no sense with --format=text')
-
- if args.format == 'text' and args.open:
- parser.error('Passing --open makes no sense with --format=text')
+ if args.format == 'text':
+ if len(args.files) != 2:
+ parser.error('--format=text requires exactly two input files to compare')
+ if args.subtitle is not None:
+ parser.error('Passing --subtitle makes no sense with --format=text')
+ if args.open:
+ parser.error('Passing --open makes no sense with --format=text')
+
+ if args.series_names is None:
+ args.series_names = ['Baseline']
+ if len(args.files) == 2:
+ args.series_names += ['Candidate']
+ elif len(args.files) > 2:
+ args.series_names.extend(f'Candidate{n}' for n in range(1, len(args.files)))
+ else:
+ args.series_names = args.series_names.split(',')
+ if len(args.series_names) != len(args.files):
+ parser.error(f'Passed incorrect number of series names: got {len(args.series_names)} series names but {len(args.files)} inputs to compare')
 
- baseline = pandas.DataFrame(parse_lnt(args.baseline.readlines()))
- candidate = pandas.DataFrame(parse_lnt(args.candidate.readlines()))
+ # Parse the raw LNT data and store each input in a dataframe
+ lnt_inputs = [parse_lnt(file.readlines()) for file in args.files]
+ inputs = [pandas.DataFrame(lnt).rename(columns={args.metric: f'{args.metric}_{i}'}) for (i, lnt) in enumerate(lnt_inputs)]
 
- # Join the baseline and the candidate into a single dataframe and add some new columns
- data = baseline.merge(candidate, how='outer', on='benchmark', suffixes=('_baseline', '_candidate'))
- data['difference'] = data[f'{args.metric}_candidate'] - data[f'{args.metric}_baseline']
- data['percent'] = 100 * (data['difference'] / data[f'{args.metric}_baseline'])
+ # Join the inputs into a single dataframe
+ data = functools.reduce(lambda a, b: a.merge(b, how='outer', on='benchmark'), inputs)
 
  if args.filter is not None:
  keeplist = [b for b in data['benchmark'] if re.search(args.filter, b) is not None]
  data = data[data['benchmark'].isin(keeplist)]
 
  if args.format == 'chart':
- figure = create_chart(data, args.metric, subtitle=args.subtitle,
- baseline_name=args.baseline_name,
- candidate_name=args.candidate_name)
+ figure = create_chart(data, args.metric, subtitle=args.subtitle, series_names=args.series_names)
  do_open = args.output is None or args.open
  output = args.output or tempfile.NamedTemporaryFile(suffix='.html').name
  plotly.io.write_html(figure, file=output, auto_open=do_open)
  else:
- diff = plain_text_comparison(data, args.metric, baseline_name=args.baseline_name,
- candidate_name=args.candidate_name)
+ diff = plain_text_comparison(data, args.metric, baseline_name=args.series_names[0],
+ candidate_name=args.series_names[1])
  diff += '\n'
  if args.output is not None:
  with open(args.output, 'w') as out: