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

On 30.08.21 20:45, Arnaldo Carvalho de Melo wrote:

Em Mon, Aug 30, 2021 at 06:47:27PM +0200, Andreas Gerstmayr escreveu:

quoted

* 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
  

quoted

Signed-off-by: Andreas Gerstmayr <redacted>
---
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