f1e0b83e7bPR-URL: https://github.com/nodejs/node/pull/61898 Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com> Reviewed-By: Filip Skokan <panva.ip@gmail.com> Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com> Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
126 lines
3.5 KiB
Python
Executable file
126 lines
3.5 KiB
Python
Executable file
#!/usr/bin/env python3
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# Copyright 2019 the V8 project authors. All rights reserved.
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# Use of this source code is governed by a BSD-style license that can be
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# found in the LICENSE file.
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"""
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python %prog trace-file
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Parses output generated by v8 with flag --trace-regexp-bytecodes and generates
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a list of the most common sequences.
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"""
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from __future__ import print_function
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import sys
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import re
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import collections
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def parse(file, seqlen):
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# example:
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# pc = 00, sp = 0, curpos = 0, curchar = 0000000a ..., PushBacktrack, label: e4
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rx = re.compile(
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r'pc = (?P<pc>[0-9a-f]+), sp = (?P<sp>\d+), '
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r'curpos = (?P<curpos>\d+), curchar = (?P<char_hex>[0-9a-f]+) '
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r'(:?\.|\()(?P<char>\.|\w)(:?\.|\)), (?P<bc>\w+), .*')
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total = 0
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# stats[len][seq_tuple] = {'count': 0, 'loops': 0}
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# Using tuple as key for easier rotation
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stats = [{} for _ in range(seqlen)]
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# last[len] = deque of (bc, pc_int)
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last = [collections.deque(maxlen=i + 1) for i in range(seqlen)]
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with open(file) as f:
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l = f.readline()
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while l:
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l = l.strip()
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if l.startswith("Start bytecode interpreter"):
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for i in range(seqlen):
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last[i].clear()
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match = rx.search(l)
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if match:
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total += 1
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bc = match.group('bc')
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pc = int(match.group('pc'), 16)
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current_node = (bc, pc)
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for i in range(seqlen):
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deque = last[i]
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if len(deque) == i + 1:
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# Canonicalize based on PC: find the rotation that starts with the
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# lowest PC. This aligns loops to their header.
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min_pc = float('inf')
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rotation_start = 0
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# Find the index with the minimum PC
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for idx, item in enumerate(deque):
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if item[1] < min_pc:
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min_pc = item[1]
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rotation_start = idx
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elif item[1] == min_pc:
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# Tie-break. If the same sequence appears twice (A->B->A->B),
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# we prefer the first.
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pass
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# Rotate to start at rotation_start
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canonical_seq = []
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for k in range(i + 1):
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idx = (rotation_start + k) % (i + 1)
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canonical_seq.append(deque[idx][0])
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seq_key = tuple(canonical_seq)
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if seq_key not in stats[i]:
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stats[i][seq_key] = {'count': 0, 'loops': 0}
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stats[i][seq_key]['count'] += 1
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# Check for loops. Note that current_node is the node *after* the
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# sequence we are currently looking at.
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first_node = deque[0]
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if current_node[1] == first_node[1]:
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stats[i][seq_key]['loops'] += 1
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deque.append(current_node)
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l = f.readline()
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return stats, total
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def print_most_common(d, seqlen, total):
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# Sort by count
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sorted_items = sorted(d.items(), key=lambda kv: kv[1]['count'], reverse=True)
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for (k, val) in sorted_items:
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count = val['count']
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loops = val['loops']
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pct = count * 100.0 / total
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if pct < 1.0:
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return
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loop_pct = loops * 100.0 / count
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seq_str = ' --> '.join(k)
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print("{}: {} ({:.2f} %) - Loops: {} ({:.2f} %)".format(
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seq_str, count, pct, loops, loop_pct))
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def main(argv):
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if len(argv) < 2:
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print("Usage: python {} <trace-file>".format(argv[0]))
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sys.exit(1)
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max_seq = 7
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stats, total = parse(argv[1], max_seq)
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for i in range(max_seq):
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print()
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print("Most common of length {}".format(i+1))
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print()
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print_most_common(stats[i], i, total)
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if __name__ == '__main__':
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main(sys.argv)
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