benchmark/tools/gbench/report.py
Roman Lebedev 886585a3b7 [RFC] Tools: compare-bench.py: print change% with two decimal digits (#440)
* Tools: compare-bench.py: print change% with two decimal digits

Here is a comparison of before vs. after:
```diff
-Benchmark                      Time           CPU      Time Old      Time New       CPU Old       CPU New
----------------------------------------------------------------------------------------------------------
-BM_SameTimes                  +0.00         +0.00            10            10            10            10
-BM_2xFaster                   -0.50         -0.50            50            25            50            25
-BM_2xSlower                   +1.00         +1.00            50           100            50           100
-BM_1PercentFaster             -0.01         -0.01           100            99           100            99
-BM_1PercentSlower             +0.01         +0.01           100           101           100           101
-BM_10PercentFaster            -0.10         -0.10           100            90           100            90
-BM_10PercentSlower            +0.10         +0.10           100           110           100           110
-BM_100xSlower                +99.00        +99.00           100         10000           100         10000
-BM_100xFaster                 -0.99         -0.99         10000           100         10000           100
-BM_10PercentCPUToTime         +0.10         -0.10           100           110           100            90
+Benchmark                        Time             CPU      Time Old      Time New       CPU Old       CPU New
+-------------------------------------------------------------------------------------------------------------
+BM_SameTimes                  +0.0000         +0.0000            10            10            10            10
+BM_2xFaster                   -0.5000         -0.5000            50            25            50            25
+BM_2xSlower                   +1.0000         +1.0000            50           100            50           100
+BM_1PercentFaster             -0.0100         -0.0100           100            99           100            99
+BM_1PercentSlower             +0.0100         +0.0100           100           101           100           101
+BM_10PercentFaster            -0.1000         -0.1000           100            90           100            90
+BM_10PercentSlower            +0.1000         +0.1000           100           110           100           110
+BM_100xSlower                +99.0000        +99.0000           100         10000           100         10000
+BM_100xFaster                 -0.9900         -0.9900         10000           100         10000           100
+BM_10PercentCPUToTime         +0.1000         -0.1000           100           110           100            90
+BM_ThirdFaster                -0.3333         -0.3333           100            67           100            67

```

So the first ("Time") column is exactly where it was, but with
two more decimal digits. The position of the '.' in the second
("CPU") column is shifted right by those two positions, and the
rest is unmodified, but simply shifted right by those 4 positions.

As for the reasoning, i guess it is more or less the same as
with #426. In some sad times, microbenchmarking is not applicable.
In those cases, the more precise the change report is, the better.

The current formatting prints not so much the percentages,
but the fraction i'd say. It is more useful for huge changes,
much more than 100%. That is not always the case, especially
if it is not a microbenchmark. Then, even though the change
may be good/bad, the change is small (<0.5% or so),
rounding happens, and it is no longer possible to tell.

I do acknowledge that this change does not fix that problem. Of
course, confidence intervals and such would be better, and they
would probably fix the problem. But i think this is good as-is
too, because now the you see 2 fractional percentage digits!1

The obvious downside is that the output is now even wider.

* Revisit tests, more closely documents the current behavior.
2017-08-28 16:12:18 -07:00

156 lines
6.0 KiB
Python

"""report.py - Utilities for reporting statistics about benchmark results
"""
import os
class BenchmarkColor(object):
def __init__(self, name, code):
self.name = name
self.code = code
def __repr__(self):
return '%s%r' % (self.__class__.__name__,
(self.name, self.code))
def __format__(self, format):
return self.code
# Benchmark Colors Enumeration
BC_NONE = BenchmarkColor('NONE', '')
BC_MAGENTA = BenchmarkColor('MAGENTA', '\033[95m')
BC_CYAN = BenchmarkColor('CYAN', '\033[96m')
BC_OKBLUE = BenchmarkColor('OKBLUE', '\033[94m')
BC_HEADER = BenchmarkColor('HEADER', '\033[92m')
BC_WARNING = BenchmarkColor('WARNING', '\033[93m')
BC_WHITE = BenchmarkColor('WHITE', '\033[97m')
BC_FAIL = BenchmarkColor('FAIL', '\033[91m')
BC_ENDC = BenchmarkColor('ENDC', '\033[0m')
BC_BOLD = BenchmarkColor('BOLD', '\033[1m')
BC_UNDERLINE = BenchmarkColor('UNDERLINE', '\033[4m')
def color_format(use_color, fmt_str, *args, **kwargs):
"""
Return the result of 'fmt_str.format(*args, **kwargs)' after transforming
'args' and 'kwargs' according to the value of 'use_color'. If 'use_color'
is False then all color codes in 'args' and 'kwargs' are replaced with
the empty string.
"""
assert use_color is True or use_color is False
if not use_color:
args = [arg if not isinstance(arg, BenchmarkColor) else BC_NONE
for arg in args]
kwargs = {key: arg if not isinstance(arg, BenchmarkColor) else BC_NONE
for key, arg in kwargs.items()}
return fmt_str.format(*args, **kwargs)
def find_longest_name(benchmark_list):
"""
Return the length of the longest benchmark name in a given list of
benchmark JSON objects
"""
longest_name = 1
for bc in benchmark_list:
if len(bc['name']) > longest_name:
longest_name = len(bc['name'])
return longest_name
def calculate_change(old_val, new_val):
"""
Return a float representing the decimal change between old_val and new_val.
"""
if old_val == 0 and new_val == 0:
return 0.0
if old_val == 0:
return float(new_val - old_val) / (float(old_val + new_val) / 2)
return float(new_val - old_val) / abs(old_val)
def generate_difference_report(json1, json2, use_color=True):
"""
Calculate and report the difference between each test of two benchmarks
runs specified as 'json1' and 'json2'.
"""
first_col_width = find_longest_name(json1['benchmarks'])
def find_test(name):
for b in json2['benchmarks']:
if b['name'] == name:
return b
return None
first_line = "{:<{}s} Time CPU Time Old Time New CPU Old CPU New".format(
'Benchmark', first_col_width)
output_strs = [first_line, '-' * len(first_line)]
gen = (bn for bn in json1['benchmarks'] if 'real_time' in bn and 'cpu_time' in bn)
for bn in gen:
other_bench = find_test(bn['name'])
if not other_bench:
continue
if bn['time_unit'] != other_bench['time_unit']:
continue
def get_color(res):
if res > 0.05:
return BC_FAIL
elif res > -0.07:
return BC_WHITE
else:
return BC_CYAN
fmt_str = "{}{:<{}s}{endc}{}{:+16.4f}{endc}{}{:+16.4f}{endc}{:14.0f}{:14.0f}{endc}{:14.0f}{:14.0f}"
tres = calculate_change(bn['real_time'], other_bench['real_time'])
cpures = calculate_change(bn['cpu_time'], other_bench['cpu_time'])
output_strs += [color_format(use_color, fmt_str,
BC_HEADER, bn['name'], first_col_width,
get_color(tres), tres, get_color(cpures), cpures,
bn['real_time'], other_bench['real_time'],
bn['cpu_time'], other_bench['cpu_time'],
endc=BC_ENDC)]
return output_strs
###############################################################################
# Unit tests
import unittest
class TestReportDifference(unittest.TestCase):
def load_results(self):
import json
testInputs = os.path.join(os.path.dirname(os.path.realpath(__file__)), 'Inputs')
testOutput1 = os.path.join(testInputs, 'test1_run1.json')
testOutput2 = os.path.join(testInputs, 'test1_run2.json')
with open(testOutput1, 'r') as f:
json1 = json.load(f)
with open(testOutput2, 'r') as f:
json2 = json.load(f)
return json1, json2
def test_basic(self):
expect_lines = [
['BM_SameTimes', '+0.0000', '+0.0000', '10', '10', '10', '10'],
['BM_2xFaster', '-0.5000', '-0.5000', '50', '25', '50', '25'],
['BM_2xSlower', '+1.0000', '+1.0000', '50', '100', '50', '100'],
['BM_1PercentFaster', '-0.0100', '-0.0100', '100', '99', '100', '99'],
['BM_1PercentSlower', '+0.0100', '+0.0100', '100', '101', '100', '101'],
['BM_10PercentFaster', '-0.1000', '-0.1000', '100', '90', '100', '90'],
['BM_10PercentSlower', '+0.1000', '+0.1000', '100', '110', '100', '110'],
['BM_100xSlower', '+99.0000', '+99.0000', '100', '10000', '100', '10000'],
['BM_100xFaster', '-0.9900', '-0.9900', '10000', '100', '10000', '100'],
['BM_10PercentCPUToTime', '+0.1000', '-0.1000', '100', '110', '100', '90'],
['BM_ThirdFaster', '-0.3333', '-0.3334', '100', '67', '100', '67'],
['BM_BadTimeUnit', '-0.9000', '+0.2000', '0', '0', '0', '1'],
]
json1, json2 = self.load_results()
output_lines_with_header = generate_difference_report(json1, json2, use_color=False)
output_lines = output_lines_with_header[2:]
print("\n".join(output_lines_with_header))
self.assertEqual(len(output_lines), len(expect_lines))
for i in range(0, len(output_lines)):
parts = [x for x in output_lines[i].split(' ') if x]
self.assertEqual(len(parts), 7)
self.assertEqual(parts, expect_lines[i])
if __name__ == '__main__':
unittest.main()