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81 lines
3.4 KiB
Python
Executable File
81 lines
3.4 KiB
Python
Executable File
#!/usr/bin/env python3
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# SPDX-License-Identifier: LGPL-2.1-or-later
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# pylint: disable=consider-using-f-string
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import gdb
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class sd_dump_hashmaps(gdb.Command):
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"dump systemd's hashmaps"
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def __init__(self):
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super().__init__('sd_dump_hashmaps', gdb.COMMAND_DATA, gdb.COMPLETE_NONE)
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def invoke(self, arg, _from_tty):
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d = gdb.parse_and_eval('hashmap_debug_list')
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hashmap_type_info = gdb.parse_and_eval('hashmap_type_info')
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uchar_t = gdb.lookup_type('unsigned char')
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ulong_t = gdb.lookup_type('unsigned long')
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debug_offset = gdb.parse_and_eval('(unsigned long)&((HashmapBase*)0)->debug')
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print('type, hash, indirect, entries, max_entries, buckets, creator')
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while d:
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h = gdb.parse_and_eval(f'(HashmapBase*)((char*){int(d.cast(ulong_t))} - {debug_offset})')
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if h['has_indirect']:
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storage_ptr = h['indirect']['storage'].cast(uchar_t.pointer())
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n_entries = h['indirect']['n_entries']
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n_buckets = h['indirect']['n_buckets']
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else:
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storage_ptr = h['direct']['storage'].cast(uchar_t.pointer())
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n_entries = h['n_direct_entries']
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n_buckets = hashmap_type_info[h['type']]['n_direct_buckets']
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t = ['plain', 'ordered', 'set'][int(h['type'])]
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print(f'{t}, {h["hash_ops"]}, {bool(h["has_indirect"])}, {n_entries}, {d["max_entries"]}, {n_buckets}') # fmt: skip
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if arg != '' and n_entries > 0:
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dib_raw_addr = storage_ptr + hashmap_type_info[h['type']]['entry_size'] * n_buckets
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histogram = {}
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for i in range(0, n_buckets):
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dib = int(dib_raw_addr[i])
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histogram[dib] = histogram.get(dib, 0) + 1
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for dib in sorted(histogram):
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if dib != 255:
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print(f'{dib:>3} {histogram[dib]:>8} {float(histogram[dib] / n_entries):.0%} of entries') # fmt: skip
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else:
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print(f'{dib:>3} {histogram[dib]:>8} {float(histogram[dib] / n_buckets):.0%} of slots') # fmt: skip
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s = sum(dib * count for (dib, count) in histogram.items() if dib != 255) / n_entries
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print(f'mean DIB of entries: {s}')
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blocks = []
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current_len = 1
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prev = int(dib_raw_addr[0])
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for i in range(1, n_buckets):
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dib = int(dib_raw_addr[i])
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if (dib == 255) != (prev == 255):
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if prev != 255:
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blocks += [[i, current_len]]
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current_len = 1
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else:
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current_len += 1
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prev = dib
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if prev != 255:
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blocks += [[i, current_len]]
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# a block may be wrapped around
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if len(blocks) > 1 and blocks[0][0] == blocks[0][1] and blocks[-1][0] == n_buckets - 1:
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blocks[0][1] += blocks[-1][1]
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blocks = blocks[0:-1]
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print(f'max block: {max(blocks, key=lambda a: a[1])}')
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print(f'sum block lens: {sum(b[1] for b in blocks)}')
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print(f'mean block len: {sum(b[1] for b in blocks) / len(blocks)}')
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d = d['debug_list_next']
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sd_dump_hashmaps()
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