Re: [PATCH] perf: flamegraph.py script improvements

[Andreas Gerstmayr <agerstmayr@redhat.com>]

On 30.08.21 20:45, Arnaldo Carvalho de Melo wrote:
> Em Mon, Aug 30, 2021 at 06:47:27PM +0200, Andreas Gerstmayr escreveu:
>> * display perf.data header
>> * display PIDs of user stacks
>> * added option to change color scheme
>> * default to blue/green color scheme to improve accessibility
>> * correctly identify kernel stacks when kernel-debuginfo is installed
> 
> I'll apply this but please next time split these changes in separate
> patches, this way we can find and fix problems faster by using 'git
> bisect'.

Ok, I'll do that next time.

Thanks for merging!


Cheers,
Andreas


> 
> - Arnaldo
>   
>> Signed-off-by: Andreas Gerstmayr <agerstmayr@redhat.com>
>> ---
>> Tested with Fedora 34, RHEL 8.5 & 9-beta, and Ubuntu 20.04.
>>
>> The updated flamegraph.py script works with the current d3-flame-graph template, but in order to use the new features (perf header, new color scheme), please run `wget -O /usr/share/d3-flame-graph/d3-flamegraph-base.html https://gist.githubusercontent.com/andreasgerstmayr/1f84a6ac04e6391bfc653a546cf3e1aa/raw/f67accc1873be66d14e90360c9b8cd15faa551f6/d3-flamegraph-base.html`
>> I'll update the js-d3-flame-graph package soon.
>>
>>
>>   tools/perf/scripts/python/flamegraph.py | 108 ++++++++++++++++++------
>>   1 file changed, 81 insertions(+), 27 deletions(-)
>>
>> diff --git a/tools/perf/scripts/python/flamegraph.py b/tools/perf/scripts/python/flamegraph.py
>> index 65780013f745..b6af1dd5f816 100755
>> --- a/tools/perf/scripts/python/flamegraph.py
>> +++ b/tools/perf/scripts/python/flamegraph.py
>> @@ -13,6 +13,10 @@
>>   # 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>
>> +#
>> +# pylint: disable=missing-module-docstring
>> +# pylint: disable=missing-class-docstring
>> +# pylint: disable=missing-function-docstring
>>   
>>   from __future__ import print_function
>>   import sys
>> @@ -20,16 +24,19 @@ import os
>>   import io
>>   import argparse
>>   import json
>> +import subprocess
>>   
>> -
>> +# pylint: disable=too-few-public-methods
>>   class Node:
>> -    def __init__(self, name, libtype=""):
>> +    def __init__(self, name, libtype):
>>           self.name = name
>> +        # "root" | "kernel" | ""
>> +        # "" indicates user space
>>           self.libtype = libtype
>>           self.value = 0
>>           self.children = []
>>   
>> -    def toJSON(self):
>> +    def to_json(self):
>>           return {
>>               "n": self.name,
>>               "l": self.libtype,
>> @@ -41,7 +48,7 @@ class Node:
>>   class FlameGraphCLI:
>>       def __init__(self, args):
>>           self.args = args
>> -        self.stack = Node("root")
>> +        self.stack = Node("all", "root")
>>   
>>           if self.args.format == "html" and \
>>                   not os.path.isfile(self.args.template):
>> @@ -53,13 +60,21 @@ class FlameGraphCLI:
>>                     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]"
>> +    @staticmethod
>> +    def get_libtype_from_dso(dso):
>> +        """
>> +        when kernel-debuginfo is installed,
>> +        dso points to /usr/lib/debug/lib/modules/*/vmlinux
>> +        """
>> +        if dso and (dso == "[kernel.kallsyms]" or dso.endswith("/vmlinux")):
>> +            return "kernel"
>>   
>> +        return ""
>> +
>> +    @staticmethod
>> +    def find_or_create_node(node, name, libtype):
>>           for child in node.children:
>> -            if child.name == name and child.libtype == libtype:
>> +            if child.name == name:
>>                   return child
>>   
>>           child = Node(name, libtype)
>> @@ -67,30 +82,65 @@ class FlameGraphCLI:
>>           return child
>>   
>>       def process_event(self, event):
>> -        node = self.find_or_create_node(self.stack, event["comm"], None)
>> +        pid = event.get("sample", {}).get("pid", 0)
>> +        # event["dso"] sometimes contains /usr/lib/debug/lib/modules/*/vmlinux
>> +        # for user-space processes; let's use pid for kernel or user-space distinction
>> +        if pid == 0:
>> +            comm = event["comm"]
>> +            libtype = "kernel"
>> +        else:
>> +            comm = "{} ({})".format(event["comm"], pid)
>> +            libtype = ""
>> +        node = self.find_or_create_node(self.stack, comm, libtype)
>> +
>>           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"))
>> +            for entry in reversed(event["callchain"]):
>> +                name = entry.get("sym", {}).get("name", "[unknown]")
>> +                libtype = self.get_libtype_from_dso(entry.get("dso"))
>> +                node = self.find_or_create_node(node, name, libtype)
>>           else:
>> -            node = self.find_or_create_node(
>> -                node, entry.get("symbol"), event.get("dso"))
>> +            name = event.get("symbol", "[unknown]")
>> +            libtype = self.get_libtype_from_dso(event.get("dso"))
>> +            node = self.find_or_create_node(node, name, libtype)
>>           node.value += 1
>>   
>> +    def get_report_header(self):
>> +        if self.args.input == "-":
>> +            # when this script is invoked with "perf script flamegraph",
>> +            # no perf.data is created and we cannot read the header of it
>> +            return ""
>> +
>> +        try:
>> +            output = subprocess.check_output(["perf", "report", "--header-only"])
>> +            return output.decode("utf-8")
>> +        except Exception as err:  # pylint: disable=broad-except
>> +            print("Error reading report header: {}".format(err), file=sys.stderr)
>> +            return ""
>> +
>>       def trace_end(self):
>> -        json_str = json.dumps(self.stack, default=lambda x: x.toJSON())
>> +        stacks_json = json.dumps(self.stack, default=lambda x: x.to_json())
>>   
>>           if self.args.format == "html":
>> +            report_header = self.get_report_header()
>> +            options = {
>> +                "colorscheme": self.args.colorscheme,
>> +                "context": report_header
>> +            }
>> +            options_json = json.dumps(options)
>> +
>>               try:
>> -                with io.open(self.args.template, encoding="utf-8") 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)
>> +                with io.open(self.args.template, encoding="utf-8") as template:
>> +                    output_str = (
>> +                        template.read()
>> +                        .replace("/** @options_json **/", options_json)
>> +                        .replace("/** @flamegraph_json **/", stacks_json)
>> +                    )
>> +            except IOError as err:
>> +                print("Error reading template file: {}".format(err), file=sys.stderr)
>>                   sys.exit(1)
>>               output_fn = self.args.output or "flamegraph.html"
>>           else:
>> -            output_str = json_str
>> +            output_str = stacks_json
>>               output_fn = self.args.output or "stacks.json"
>>   
>>           if output_fn == "-":
>> @@ -101,8 +151,8 @@ class FlameGraphCLI:
>>               try:
>>                   with io.open(output_fn, "w", encoding="utf-8") as out:
>>                       out.write(output_str)
>> -            except IOError as e:
>> -                print("Error writing output file: {}".format(e), file=sys.stderr)
>> +            except IOError as err:
>> +                print("Error writing output file: {}".format(err), file=sys.stderr)
>>                   sys.exit(1)
>>   
>>   
>> @@ -115,12 +165,16 @@ if __name__ == "__main__":
>>                           help="output file name")
>>       parser.add_argument("--template",
>>                           default="/usr/share/d3-flame-graph/d3-flamegraph-base.html",
>> -                        help="path to flamegraph HTML template")
>> +                        help="path to flame graph HTML template")
>> +    parser.add_argument("--colorscheme",
>> +                        default="blue-green",
>> +                        help="flame graph color scheme",
>> +                        choices=["blue-green", "orange"])
>>       parser.add_argument("-i", "--input",
>>                           help=argparse.SUPPRESS)
>>   
>> -    args = parser.parse_args()
>> -    cli = FlameGraphCLI(args)
>> +    cli_args = parser.parse_args()
>> +    cli = FlameGraphCLI(cli_args)
>>   
>>       process_event = cli.process_event
>>       trace_end = cli.trace_end
>> -- 
>> 2.31.1
>