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systemd/tools/gdb-sd_dump_hashmaps.py
Michal Schmidt 2ea8c08306 tools: add gdb command to dump hashmap information
$ sudo gdb -p 1
...
(gdb) source gdb-sd_dump_hashmaps.py
(gdb) sd_dump_hashmaps
  ... lists allocated hashmaps ...
(gdb) sd_dump_hashmaps 1
  ... lists allocated hashmaps, their DIB histograms and contiguous
      blocks statistics ...
2014-10-30 19:50:51 +01:00

95 lines
5.0 KiB
Python

# -*- Mode: python; coding: utf-8; indent-tabs-mode: nil -*- */
#
# This file is part of systemd.
#
# Copyright 2014 Michal Schmidt
#
# systemd is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# systemd is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with systemd; If not, see <http://www.gnu.org/licenses/>.
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")
hashmap_base_t = gdb.lookup_type("HashmapBase")
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 "%s, %s, %s, %d, %d, %d, %s (%s:%d)" % (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 "%3d %8d %f%% of entries" % (dib, histogram[dib], 100.0*histogram[dib]/n_entries)
else:
print "%3d %8d %f%% of slots" % (dib, histogram[dib], 100.0*histogram[dib]/n_buckets)
print "mean DIB of entries: %f" % (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: %s" % max(blocks, key=lambda a: a[1])
print "sum block lens: %d" % sum(b[1] for b in blocks)
print "mean block len: %f" % (1.0 * sum(b[1] for b in blocks) / len(blocks))
d = d["debug_list_next"]
sd_dump_hashmaps()