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systemd/tools/gdb-sd_dump_hashmaps.py

80 lines
4.3 KiB
Python

#!/usr/bin/env python3
# SPDX-License-Identifier: LGPL-2.1+
from __future__ import print_function
import gdb
class sd_dump_hashmaps(gdb.Command):
"dump systemd's hashmaps"
def __init__(self):
super(sd_dump_hashmaps, self).__init__("sd_dump_hashmaps", gdb.COMMAND_DATA, gdb.COMPLETE_NONE)
def invoke(self, arg, from_tty):
d = gdb.parse_and_eval("hashmap_debug_list")
all_entry_sizes = gdb.parse_and_eval("all_entry_sizes")
all_direct_buckets = gdb.parse_and_eval("all_direct_buckets")
uchar_t = gdb.lookup_type("unsigned char")
ulong_t = gdb.lookup_type("unsigned long")
debug_offset = gdb.parse_and_eval("(unsigned long)&((HashmapBase*)0)->debug")
print("type, hash, indirect, entries, max_entries, buckets, creator")
while d:
h = gdb.parse_and_eval("(HashmapBase*)((char*)%d - %d)" % (int(d.cast(ulong_t)), debug_offset))
if h["has_indirect"]:
storage_ptr = h["indirect"]["storage"].cast(uchar_t.pointer())
n_entries = h["indirect"]["n_entries"]
n_buckets = h["indirect"]["n_buckets"]
else:
storage_ptr = h["direct"]["storage"].cast(uchar_t.pointer())
n_entries = h["n_direct_entries"]
n_buckets = all_direct_buckets[int(h["type"])];
t = ["plain", "ordered", "set"][int(h["type"])]
print("{}, {}, {}, {}, {}, {}, {} ({}:{})".format(t, h["hash_ops"], bool(h["has_indirect"]), n_entries, d["max_entries"], n_buckets, d["func"], d["file"], d["line"]))
if arg != "" and n_entries > 0:
dib_raw_addr = storage_ptr + (all_entry_sizes[h["type"]] * n_buckets)
histogram = {}
for i in xrange(0, n_buckets):
dib = int(dib_raw_addr[i])
histogram[dib] = histogram.get(dib, 0) + 1
for dib in sorted(iter(histogram)):
if dib != 255:
print("{:>3} {:>8} {} of entries".format(dib, histogram[dib], 100.0*histogram[dib]/n_entries))
else:
print("{:>3} {:>8} {} of slots".format(dib, histogram[dib], 100.0*histogram[dib]/n_buckets))
print("mean DIB of entries: {}".format(sum([dib*histogram[dib] for dib in iter(histogram) if dib != 255])*1.0/n_entries))
blocks = []
current_len = 1
prev = int(dib_raw_addr[0])
for i in xrange(1, n_buckets):
dib = int(dib_raw_addr[i])
if (dib == 255) != (prev == 255):
if prev != 255:
blocks += [[i, current_len]]
current_len = 1
else:
current_len += 1
prev = dib
if prev != 255:
blocks += [[i, current_len]]
# a block may be wrapped around
if len(blocks) > 1 and blocks[0][0] == blocks[0][1] and blocks[-1][0] == n_buckets - 1:
blocks[0][1] += blocks[-1][1]
blocks = blocks[0:-1]
print("max block: {}".format(max(blocks, key=lambda a: a[1])))
print("sum block lens: {}".format(sum(b[1] for b in blocks)))
print("mean block len: {}".format((1.0 * sum(b[1] for b in blocks) / len(blocks))))
d = d["debug_list_next"]
sd_dump_hashmaps()