]>
Commit | Line | Data |
---|---|---|
4877829b ML |
1 | #!/usr/bin/env python3 |
2 | # | |
3 | # Script to analyze results of our branch prediction heuristics | |
4 | # | |
5 | # This file is part of GCC. | |
6 | # | |
7 | # GCC is free software; you can redistribute it and/or modify it under | |
8 | # the terms of the GNU General Public License as published by the Free | |
9 | # Software Foundation; either version 3, or (at your option) any later | |
10 | # version. | |
11 | # | |
12 | # GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
13 | # WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | # FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | # for more details. | |
16 | # | |
17 | # You should have received a copy of the GNU General Public License | |
18 | # along with GCC; see the file COPYING3. If not see | |
19 | # <http://www.gnu.org/licenses/>. */ | |
20 | # | |
21 | # | |
22 | # | |
23 | # This script is used to calculate two basic properties of the branch prediction | |
24 | # heuristics - coverage and hitrate. Coverage is number of executions | |
25 | # of a given branch matched by the heuristics and hitrate is probability | |
26 | # that once branch is predicted as taken it is really taken. | |
27 | # | |
28 | # These values are useful to determine the quality of given heuristics. | |
29 | # Hitrate may be directly used in predict.def. | |
30 | # | |
31 | # Usage: | |
32 | # Step 1: Compile and profile your program. You need to use -fprofile-generate | |
33 | # flag to get the profiles. | |
34 | # Step 2: Make a reference run of the intrumented application. | |
35 | # Step 3: Compile the program with collected profile and dump IPA profiles | |
36 | # (-fprofile-use -fdump-ipa-profile-details) | |
37 | # Step 4: Collect all generated dump files: | |
38 | # find . -name '*.profile' | xargs cat > dump_file | |
39 | # Step 5: Run the script: | |
40 | # ./analyze_brprob.py dump_file | |
41 | # and read results. Basically the following table is printed: | |
42 | # | |
43 | # HEURISTICS BRANCHES (REL) HITRATE COVERAGE (REL) | |
44 | # early return (on trees) 3 0.2% 35.83% / 93.64% 66360 0.0% | |
45 | # guess loop iv compare 8 0.6% 53.35% / 53.73% 11183344 0.0% | |
46 | # call 18 1.4% 31.95% / 69.95% 51880179 0.2% | |
47 | # loop guard 23 1.8% 84.13% / 84.85% 13749065956 42.2% | |
48 | # opcode values positive (on trees) 42 3.3% 15.71% / 84.81% 6771097902 20.8% | |
49 | # opcode values nonequal (on trees) 226 17.6% 72.48% / 72.84% 844753864 2.6% | |
50 | # loop exit 231 18.0% 86.97% / 86.98% 8952666897 27.5% | |
51 | # loop iterations 239 18.6% 91.10% / 91.10% 3062707264 9.4% | |
52 | # DS theory 281 21.9% 82.08% / 83.39% 7787264075 23.9% | |
53 | # no prediction 293 22.9% 46.92% / 70.70% 2293267840 7.0% | |
54 | # guessed loop iterations 313 24.4% 76.41% / 76.41% 10782750177 33.1% | |
55 | # first match 708 55.2% 82.30% / 82.31% 22489588691 69.0% | |
56 | # combined 1282 100.0% 79.76% / 81.75% 32570120606 100.0% | |
57 | # | |
58 | # | |
59 | # The heuristics called "first match" is a heuristics used by GCC branch | |
60 | # prediction pass and it predicts 55.2% branches correctly. As you can, | |
61 | # the heuristics has very good covertage (69.05%). On the other hand, | |
62 | # "opcode values nonequal (on trees)" heuristics has good hirate, but poor | |
63 | # coverage. | |
64 | ||
65 | import sys | |
66 | import os | |
67 | import re | |
0d73e480 | 68 | import argparse |
4877829b | 69 | |
199b1891 ML |
70 | from math import * |
71 | ||
ca3b6071 ML |
72 | counter_aggregates = set(['combined', 'first match', 'DS theory', |
73 | 'no prediction']) | |
74 | ||
4877829b ML |
75 | def percentage(a, b): |
76 | return 100.0 * a / b | |
77 | ||
199b1891 ML |
78 | def average(values): |
79 | return 1.0 * sum(values) / len(values) | |
80 | ||
81 | def average_cutoff(values, cut): | |
82 | l = len(values) | |
83 | skip = floor(l * cut / 2) | |
84 | if skip > 0: | |
85 | values.sort() | |
86 | values = values[skip:-skip] | |
87 | return average(values) | |
88 | ||
89 | def median(values): | |
90 | values.sort() | |
91 | return values[int(len(values) / 2)] | |
92 | ||
59075bc8 ML |
93 | class PredictDefFile: |
94 | def __init__(self, path): | |
95 | self.path = path | |
96 | self.predictors = {} | |
97 | ||
98 | def parse_and_modify(self, heuristics, write_def_file): | |
99 | lines = [x.rstrip() for x in open(self.path).readlines()] | |
100 | ||
101 | p = None | |
102 | modified_lines = [] | |
103 | for l in lines: | |
104 | if l.startswith('DEF_PREDICTOR'): | |
105 | m = re.match('.*"(.*)".*', l) | |
106 | p = m.group(1) | |
107 | elif l == '': | |
108 | p = None | |
109 | ||
110 | if p != None: | |
111 | heuristic = [x for x in heuristics if x.name == p] | |
112 | heuristic = heuristic[0] if len(heuristic) == 1 else None | |
113 | ||
114 | m = re.match('.*HITRATE \(([^)]*)\).*', l) | |
115 | if (m != None): | |
116 | self.predictors[p] = int(m.group(1)) | |
117 | ||
118 | # modify the line | |
119 | if heuristic != None: | |
120 | new_line = (l[:m.start(1)] | |
121 | + str(round(heuristic.get_hitrate())) | |
122 | + l[m.end(1):]) | |
123 | l = new_line | |
124 | p = None | |
125 | elif 'PROB_VERY_LIKELY' in l: | |
126 | self.predictors[p] = 100 | |
127 | modified_lines.append(l) | |
128 | ||
129 | # save the file | |
130 | if write_def_file: | |
131 | with open(self.path, 'w+') as f: | |
132 | for l in modified_lines: | |
133 | f.write(l + '\n') | |
134 | ||
4877829b ML |
135 | class Summary: |
136 | def __init__(self, name): | |
137 | self.name = name | |
138 | self.branches = 0 | |
ca3b6071 | 139 | self.successfull_branches = 0 |
4877829b ML |
140 | self.count = 0 |
141 | self.hits = 0 | |
142 | self.fits = 0 | |
143 | ||
0d73e480 | 144 | def get_hitrate(self): |
ca3b6071 ML |
145 | return 100.0 * self.hits / self.count |
146 | ||
147 | def get_branch_hitrate(self): | |
148 | return 100.0 * self.successfull_branches / self.branches | |
0d73e480 | 149 | |
4877829b ML |
150 | def count_formatted(self): |
151 | v = self.count | |
152 | for unit in ['','K','M','G','T','P','E','Z']: | |
153 | if v < 1000: | |
154 | return "%3.2f%s" % (v, unit) | |
155 | v /= 1000.0 | |
156 | return "%.1f%s" % (v, 'Y') | |
157 | ||
59075bc8 ML |
158 | def print(self, branches_max, count_max, predict_def): |
159 | predicted_as = None | |
160 | if predict_def != None and self.name in predict_def.predictors: | |
161 | predicted_as = predict_def.predictors[self.name] | |
162 | ||
ca3b6071 ML |
163 | print('%-40s %8i %5.1f%% %11.2f%% %7.2f%% / %6.2f%% %14i %8s %5.1f%%' % |
164 | (self.name, self.branches, | |
165 | percentage(self.branches, branches_max), | |
166 | self.get_branch_hitrate(), | |
167 | self.get_hitrate(), | |
168 | percentage(self.fits, self.count), | |
169 | self.count, self.count_formatted(), | |
59075bc8 ML |
170 | percentage(self.count, count_max)), end = '') |
171 | ||
172 | if predicted_as != None: | |
173 | print('%12i%% %5.1f%%' % (predicted_as, | |
174 | self.get_hitrate() - predicted_as), end = '') | |
175 | print() | |
ca3b6071 | 176 | |
4877829b ML |
177 | class Profile: |
178 | def __init__(self, filename): | |
179 | self.filename = filename | |
180 | self.heuristics = {} | |
199b1891 | 181 | self.niter_vector = [] |
4877829b ML |
182 | |
183 | def add(self, name, prediction, count, hits): | |
184 | if not name in self.heuristics: | |
185 | self.heuristics[name] = Summary(name) | |
186 | ||
187 | s = self.heuristics[name] | |
188 | s.branches += 1 | |
ca3b6071 | 189 | |
4877829b ML |
190 | s.count += count |
191 | if prediction < 50: | |
192 | hits = count - hits | |
ca3b6071 ML |
193 | remaining = count - hits |
194 | if hits >= remaining: | |
195 | s.successfull_branches += 1 | |
196 | ||
4877829b | 197 | s.hits += hits |
ca3b6071 | 198 | s.fits += max(hits, remaining) |
4877829b | 199 | |
199b1891 ML |
200 | def add_loop_niter(self, niter): |
201 | if niter > 0: | |
202 | self.niter_vector.append(niter) | |
203 | ||
4877829b ML |
204 | def branches_max(self): |
205 | return max([v.branches for k, v in self.heuristics.items()]) | |
206 | ||
207 | def count_max(self): | |
208 | return max([v.count for k, v in self.heuristics.items()]) | |
209 | ||
59075bc8 | 210 | def print_group(self, sorting, group_name, heuristics, predict_def): |
ca3b6071 ML |
211 | count_max = self.count_max() |
212 | branches_max = self.branches_max() | |
213 | ||
214 | sorter = lambda x: x.branches | |
215 | if sorting == 'branch-hitrate': | |
216 | sorter = lambda x: x.get_branch_hitrate() | |
217 | elif sorting == 'hitrate': | |
218 | sorter = lambda x: x.get_hitrate() | |
0d73e480 | 219 | elif sorting == 'coverage': |
ca3b6071 ML |
220 | sorter = lambda x: x.count |
221 | elif sorting == 'name': | |
222 | sorter = lambda x: x.name.lower() | |
223 | ||
59075bc8 | 224 | print('%-40s %8s %6s %12s %18s %14s %8s %6s %12s %6s' % |
ca3b6071 | 225 | ('HEURISTICS', 'BRANCHES', '(REL)', |
59075bc8 ML |
226 | 'BR. HITRATE', 'HITRATE', 'COVERAGE', 'COVERAGE', '(REL)', |
227 | 'predict.def', '(REL)')) | |
ca3b6071 | 228 | for h in sorted(heuristics, key = sorter): |
59075bc8 | 229 | h.print(branches_max, count_max, predict_def) |
ca3b6071 ML |
230 | |
231 | def dump(self, sorting): | |
232 | heuristics = self.heuristics.values() | |
233 | if len(heuristics) == 0: | |
234 | print('No heuristics available') | |
235 | return | |
236 | ||
59075bc8 ML |
237 | predict_def = None |
238 | if args.def_file != None: | |
239 | predict_def = PredictDefFile(args.def_file) | |
240 | predict_def.parse_and_modify(heuristics, args.write_def_file) | |
241 | ||
ca3b6071 ML |
242 | special = list(filter(lambda x: x.name in counter_aggregates, |
243 | heuristics)) | |
244 | normal = list(filter(lambda x: x.name not in counter_aggregates, | |
245 | heuristics)) | |
0d73e480 | 246 | |
59075bc8 | 247 | self.print_group(sorting, 'HEURISTICS', normal, predict_def) |
ca3b6071 | 248 | print() |
59075bc8 | 249 | self.print_group(sorting, 'HEURISTIC AGGREGATES', special, predict_def) |
4877829b | 250 | |
88617fe4 ML |
251 | if len(self.niter_vector) > 0: |
252 | print ('\nLoop count: %d' % len(self.niter_vector)), | |
253 | print(' avg. # of iter: %.2f' % average(self.niter_vector)) | |
254 | print(' median # of iter: %.2f' % median(self.niter_vector)) | |
255 | for v in [1, 5, 10, 20, 30]: | |
256 | cut = 0.01 * v | |
ca3b6071 ML |
257 | print(' avg. (%d%% cutoff) # of iter: %.2f' |
258 | % (v, average_cutoff(self.niter_vector, cut))) | |
199b1891 | 259 | |
0d73e480 | 260 | parser = argparse.ArgumentParser() |
ca3b6071 ML |
261 | parser.add_argument('dump_file', metavar = 'dump_file', |
262 | help = 'IPA profile dump file') | |
263 | parser.add_argument('-s', '--sorting', dest = 'sorting', | |
264 | choices = ['branches', 'branch-hitrate', 'hitrate', 'coverage', 'name'], | |
265 | default = 'branches') | |
59075bc8 ML |
266 | parser.add_argument('-d', '--def-file', help = 'path to predict.def') |
267 | parser.add_argument('-w', '--write-def-file', action = 'store_true', | |
268 | help = 'Modify predict.def file in order to set new numbers') | |
0d73e480 ML |
269 | |
270 | args = parser.parse_args() | |
4877829b | 271 | |
59075bc8 | 272 | profile = Profile(args.dump_file) |
e49efc14 | 273 | r = re.compile(' (.*) heuristics( of edge [0-9]*->[0-9]*)?( \\(.*\\))?: (.*)%.*exec ([0-9]*) hit ([0-9]*)') |
199b1891 | 274 | loop_niter_str = ';; profile-based iteration count: ' |
59075bc8 | 275 | for l in open(args.dump_file): |
4877829b | 276 | m = r.match(l) |
e49efc14 | 277 | if m != None and m.group(3) == None: |
4877829b | 278 | name = m.group(1) |
e49efc14 ML |
279 | prediction = float(m.group(4)) |
280 | count = int(m.group(5)) | |
281 | hits = int(m.group(6)) | |
4877829b ML |
282 | |
283 | profile.add(name, prediction, count, hits) | |
199b1891 ML |
284 | elif l.startswith(loop_niter_str): |
285 | v = int(l[len(loop_niter_str):]) | |
286 | profile.add_loop_niter(v) | |
4877829b | 287 | |
0d73e480 | 288 | profile.dump(args.sorting) |