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#!/usr/bin/env python
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at
# Firefox about:memory log parser.
from __future__ import absolute_import, print_function
import argparse
from collections import defaultdict
import gzip
import json
# This value comes from nsIMemoryReporter.idl.
def path_total(data, path):
Calculates the sum for the given data point path and its children. If
path does not end with a '/' then only the value for the exact path is
path_totals = defaultdict(int)
# Bookkeeping for calculating the heap-unclassified measurement.
explicit_heap = defaultdict(int)
heap_allocated = defaultdict(int)
discrete = not path.endswith("/")
def match(value):
Helper that performs either an explicit match or a prefix match
depending on the format of the path passed in.
if discrete:
return value == path
return value.startswith(path)
def update_bookkeeping(report):
Adds the value to the heap total if this an explicit entry that is a
heap measurement and updates the heap allocated value if necessary.
if report["kind"] == KIND_HEAP and report["path"].startswith("explicit/"):
explicit_heap[report["process"]] += report["amount"]
elif report["path"] == "heap-allocated":
heap_allocated[report["process"]] = report["amount"]
def heap_unclassified(process):
Calculates the heap-unclassified value for the given process. This is
simply the difference between all values reported as heap allocated
under the explicit/ tree and the value reported for heap-allocated by
the allocator.
# Memory reports should always include heap-allocated. If it's missing
# just assert.
assert process in heap_allocated
unclassified = heap_allocated[process] - explicit_heap[process]
# Make sure the value is sane. A misbehaving reporter could lead to
# negative values.
assert unclassified >= 0, "heap-unclassified was negative: %d" % unclassified
return unclassified
needs_bookkeeping = path in ("explicit/", "explicit/heap-unclassified")
# Process all the reports.
for report in data["reports"]:
if needs_bookkeeping:
if match(report["path"]):
path_totals[report["process"]] += report["amount"]
# Handle special processing for explicit and heap-unclassified.
if path == "explicit/":
# If 'explicit/' is requested we need to add the 'explicit/heap-unclassified'
# node that is generated by about:memory.
for k, v in explicit_heap.items():
path_totals[k] += heap_unclassified(k)
elif path == "explicit/heap-unclassified":
# If 'explicit/heap-unclassified' is requested we need to calculate the
# value as it's generated by about:memory, not explicitly reported.
for k, v in explicit_heap.items():
path_totals[k] = heap_unclassified(k)
return path_totals
def calculate_memory_report_values(
memory_report_path, data_point_path, process_names=None
Opens the given memory report file and calculates the value for the given
data point.
:param memory_report_path: Path to the memory report file to parse.
:param data_point_path: Path of the data point to calculate in the memory
report, ie: 'explicit/heap-unclassified'.
:param process_name: Name of processes to limit reports to. ie 'Main'
with open(memory_report_path) as f:
data = json.load(f)
except ValueError:
# Check if the file is gzipped.
with, "rb") as f:
data = json.load(f)
totals = path_total(data, data_point_path)
# If a process name is provided, restricted output to processes matching
# that name.
if process_names is not None:
for k in list(totals.keys()):
if not any([process_name in k for process_name in process_names]):
del totals[k]
return totals
if __name__ == "__main__":
parser = argparse.ArgumentParser(
description="Extract data points from about:memory reports"
parser.add_argument("report", action="store", help="Path to a memory report file.")
help="Prefix of data point to measure. "
"If the prefix does not end in a '/' "
"then an exact match is made.",
help="Process name filter. " "If not provided all processes will be included.",
help="Output values as mebibytes (instead of bytes)" " to match about:memory.",
args = parser.parse_args()
totals = calculate_memory_report_values(, args.prefix, args.proc_filter)
sorted_totals = sorted(totals.items(), key=lambda item: (-item[1], item[0]))
for (k, v) in sorted_totals:
if v:
bytes_per_mebibyte = 1024.0 * 1024.0
for (k, v) in sorted_totals:
if v:
if args.mebi:
print("{0:.2f} MiB".format(v / bytes_per_mebibyte)),
print("{0} bytes".format(v)),