1# flamegraph.py - create flame graphs from perf samples
2# SPDX-License-Identifier: GPL-2.0
3#
4# Usage:
5#
6#     perf record -a -g -F 99 sleep 60
7#     perf script report flamegraph
8#
9# Combined:
10#
11#     perf script flamegraph -a -F 99 sleep 60
12#
13# Written by Andreas Gerstmayr <agerstmayr@redhat.com>
14# Flame Graphs invented by Brendan Gregg <bgregg@netflix.com>
15# Works in tandem with d3-flame-graph by Martin Spier <mspier@netflix.com>
16#
17# pylint: disable=missing-module-docstring
18# pylint: disable=missing-class-docstring
19# pylint: disable=missing-function-docstring
20
21from __future__ import print_function
22import sys
23import os
24import io
25import argparse
26import json
27import subprocess
28
29# pylint: disable=too-few-public-methods
30class Node:
31    def __init__(self, name, libtype):
32        self.name = name
33        # "root" | "kernel" | ""
34        # "" indicates user space
35        self.libtype = libtype
36        self.value = 0
37        self.children = []
38
39    def to_json(self):
40        return {
41            "n": self.name,
42            "l": self.libtype,
43            "v": self.value,
44            "c": self.children
45        }
46
47
48class FlameGraphCLI:
49    def __init__(self, args):
50        self.args = args
51        self.stack = Node("all", "root")
52
53        if self.args.format == "html" and \
54                not os.path.isfile(self.args.template):
55            print("Flame Graph template {} does not exist. Please install "
56                  "the js-d3-flame-graph (RPM) or libjs-d3-flame-graph (deb) "
57                  "package, specify an existing flame graph template "
58                  "(--template PATH) or another output format "
59                  "(--format FORMAT).".format(self.args.template),
60                  file=sys.stderr)
61            sys.exit(1)
62
63    @staticmethod
64    def get_libtype_from_dso(dso):
65        """
66        when kernel-debuginfo is installed,
67        dso points to /usr/lib/debug/lib/modules/*/vmlinux
68        """
69        if dso and (dso == "[kernel.kallsyms]" or dso.endswith("/vmlinux")):
70            return "kernel"
71
72        return ""
73
74    @staticmethod
75    def find_or_create_node(node, name, libtype):
76        for child in node.children:
77            if child.name == name:
78                return child
79
80        child = Node(name, libtype)
81        node.children.append(child)
82        return child
83
84    def process_event(self, event):
85        pid = event.get("sample", {}).get("pid", 0)
86        # event["dso"] sometimes contains /usr/lib/debug/lib/modules/*/vmlinux
87        # for user-space processes; let's use pid for kernel or user-space distinction
88        if pid == 0:
89            comm = event["comm"]
90            libtype = "kernel"
91        else:
92            comm = "{} ({})".format(event["comm"], pid)
93            libtype = ""
94        node = self.find_or_create_node(self.stack, comm, libtype)
95
96        if "callchain" in event:
97            for entry in reversed(event["callchain"]):
98                name = entry.get("sym", {}).get("name", "[unknown]")
99                libtype = self.get_libtype_from_dso(entry.get("dso"))
100                node = self.find_or_create_node(node, name, libtype)
101        else:
102            name = event.get("symbol", "[unknown]")
103            libtype = self.get_libtype_from_dso(event.get("dso"))
104            node = self.find_or_create_node(node, name, libtype)
105        node.value += 1
106
107    def get_report_header(self):
108        if self.args.input == "-":
109            # when this script is invoked with "perf script flamegraph",
110            # no perf.data is created and we cannot read the header of it
111            return ""
112
113        try:
114            output = subprocess.check_output(["perf", "report", "--header-only"])
115            return output.decode("utf-8")
116        except Exception as err:  # pylint: disable=broad-except
117            print("Error reading report header: {}".format(err), file=sys.stderr)
118            return ""
119
120    def trace_end(self):
121        stacks_json = json.dumps(self.stack, default=lambda x: x.to_json())
122
123        if self.args.format == "html":
124            report_header = self.get_report_header()
125            options = {
126                "colorscheme": self.args.colorscheme,
127                "context": report_header
128            }
129            options_json = json.dumps(options)
130
131            try:
132                with io.open(self.args.template, encoding="utf-8") as template:
133                    output_str = (
134                        template.read()
135                        .replace("/** @options_json **/", options_json)
136                        .replace("/** @flamegraph_json **/", stacks_json)
137                    )
138            except IOError as err:
139                print("Error reading template file: {}".format(err), file=sys.stderr)
140                sys.exit(1)
141            output_fn = self.args.output or "flamegraph.html"
142        else:
143            output_str = stacks_json
144            output_fn = self.args.output or "stacks.json"
145
146        if output_fn == "-":
147            with io.open(sys.stdout.fileno(), "w", encoding="utf-8", closefd=False) as out:
148                out.write(output_str)
149        else:
150            print("dumping data to {}".format(output_fn))
151            try:
152                with io.open(output_fn, "w", encoding="utf-8") as out:
153                    out.write(output_str)
154            except IOError as err:
155                print("Error writing output file: {}".format(err), file=sys.stderr)
156                sys.exit(1)
157
158
159if __name__ == "__main__":
160    parser = argparse.ArgumentParser(description="Create flame graphs.")
161    parser.add_argument("-f", "--format",
162                        default="html", choices=["json", "html"],
163                        help="output file format")
164    parser.add_argument("-o", "--output",
165                        help="output file name")
166    parser.add_argument("--template",
167                        default="/usr/share/d3-flame-graph/d3-flamegraph-base.html",
168                        help="path to flame graph HTML template")
169    parser.add_argument("--colorscheme",
170                        default="blue-green",
171                        help="flame graph color scheme",
172                        choices=["blue-green", "orange"])
173    parser.add_argument("-i", "--input",
174                        help=argparse.SUPPRESS)
175
176    cli_args = parser.parse_args()
177    cli = FlameGraphCLI(cli_args)
178
179    process_event = cli.process_event
180    trace_end = cli.trace_end
181