perf script: Add flamegraph.py script

#!/usr/bin/sh

perf record -g "$@"

#!/usr/bin/sh

# description: create flame graphs

perf script -s "$PERF_EXEC_PATH"/scripts/python/flamegraph.py -- "$@"

# flamegraph.py - create flame graphs from perf samples

# SPDX-License-Identifier: GPL-2.0

#

# Usage:

#

#     perf record -a -g -F 99 sleep 60

#     perf script report flamegraph

#

# Combined:

#

#     perf script flamegraph -a -F 99 sleep 60

#

# Written by Andreas Gerstmayr <agerstmayr@redhat.com>

# Flame Graphs invented by Brendan Gregg <bgregg@netflix.com>

# Works in tandem with d3-flame-graph by Martin Spier <mspier@netflix.com>

from __future__ import print_function

import sys

import os

import argparse

import json

class Node:

    def __init__(self, name, libtype=""):

        self.name = name

        self.libtype = libtype

        self.value = 0

        self.children = []

    def toJSON(self):

        return {

            "n": self.name,

            "l": self.libtype,

            "v": self.value,

            "c": self.children

        }

class FlameGraphCLI:

    def __init__(self, args):

        self.args = args

        self.stack = Node("root")

        if self.args.format == "html" and \

                not os.path.isfile(self.args.template):

            print("Flame Graph template {} does not exist. Please install "

                  "the js-d3-flame-graph (RPM) or libjs-d3-flame-graph (deb) "

                  "package, specify an existing flame graph template "

                  "(--template PATH) or another output format "

                  "(--format FORMAT).".format(self.args.template),

                  file=sys.stderr)

            sys.exit(1)

    def find_or_create_node(self, node, name, dso):

        libtype = "kernel" if dso == "[kernel.kallsyms]" else ""

        if name is None:

            name = "[unknown]"

        for child in node.children:

            if child.name == name and child.libtype == libtype:

                return child

        child = Node(name, libtype)

        node.children.append(child)

        return child

    def process_event(self, event):

        node = self.find_or_create_node(self.stack, event["comm"], None)

        if "callchain" in event:

            for entry in reversed(event['callchain']):

                node = self.find_or_create_node(

                    node, entry.get("sym", {}).get("name"), event.get("dso"))

        else:

            node = self.find_or_create_node(

                node, entry.get("symbol"), event.get("dso"))

        node.value += 1

    def trace_end(self):

        json_str = json.dumps(self.stack, default=lambda x: x.toJSON())

        if self.args.format == "html":

            try:

                with open(self.args.template) as f:

                    output_str = f.read().replace("/** @flamegraph_json **/",

                                                  json_str)

            except IOError as e:

                print("Error reading template file: {}".format(e), file=sys.stderr)

                sys.exit(1)

            output_fn = self.args.output or "flamegraph.html"

        else:

            output_str = json_str

            output_fn = self.args.output or "stacks.json"

        if output_fn == "-":

            sys.stdout.write(output_str)

        else:

            print("dumping data to {}".format(output_fn))

            try:

                with open(output_fn, "w") as out:

                    out.write(output_str)

            except IOError as e:

                print("Error writing output file: {}".format(e), file=sys.stderr)

                sys.exit(1)

if __name__ == "__main__":

    parser = argparse.ArgumentParser(description="Create flame graphs.")

    parser.add_argument("-f", "--format",

                        default="html", choices=["json", "html"],

                        help="output file format")

    parser.add_argument("-o", "--output",

                        help="output file name")

    parser.add_argument("--template",

                        default="/usr/share/d3-flame-graph/d3-flamegraph-base.html",

                        help="path to flamegraph HTML template")

    parser.add_argument("-i", "--input",

                        help=argparse.SUPPRESS)

    args = parser.parse_args()

    cli = FlameGraphCLI(args)

    process_event = cli.process_event

    trace_end = cli.trace_end