dev/stackdiff-dtrace: stack aggregation diffing script (#1373)

Motivation:

NIO has allocation counter tests, NIO also has dev/malloc-aggregation.d
which can give you aggregated stacks that allocated alongside how many
times they allocated. What's missing is a script that can diff two
aggregated stack traces.

Modifications:

Add dev/stacktrace-dtrace which allows aggregated stack trace diffing.

Result:

Easier to track performance regressions.

dev/stackdiff-dtrace.py

@@ -0,0 +1,93 @@
+#!/usr/bin/env python
+##===----------------------------------------------------------------------===##
+##
+## This source file is part of the SwiftNIO open source project
+##
+## Copyright (c) 2020 Apple Inc. and the SwiftNIO project authors
+## Licensed under Apache License v2.0
+##
+## See LICENSE.txt for license information
+## See CONTRIBUTORS.txt for the list of SwiftNIO project authors
+##
+## SPDX-License-Identifier: Apache-2.0
+##
+##===----------------------------------------------------------------------===##
+
+import sys
+import re
+
+num_regex = "^ +([0-9a-fx]+)$"
+stack_regex = "^ +(.*)$"
+
+def put_in_dict(path):
+    dictionary = {}
+    with open(path, "r") as f:
+        current_text = ""
+        for line in f:
+            if line == "":
+                break
+            if re.match(num_regex, line):
+                key = "\n".join(map(lambda l: l.strip().split("+")[0],
+                                    current_text.split("\n")[0:8]))
+                dictionary[key] = (int(line), current_text)
+                current_text = ""
+            elif line.strip() == "":
+                pass
+            else:
+                current_text = current_text + line.strip() + "\n"
+    return dictionary
+
+def extract_useful_keys(d):
+    keys = set()
+    for k in d.keys():
+        if d[k][0] > 1000:
+            keys.add(k)
+    return keys
+
+def usage():
+    print("Usage: stackdiff-dtrace.py OLD-STACKS NEW-STACKS")
+    print()
+    print("stackdiff-dtrace can diff aggregated stack traces as produced")
+    print("by a `agg[ustack()] = count();` and printed with `printa(agg)`;")
+    print("by a dtrace program.")
+    print()
+    print("Full example leveraging the malloc aggregation:")
+    print("  # get old stack traces")
+    print("  sudo malloc-aggregation.d -c ./old-binary > /tmp/old")
+    print("  # get new stack traces")
+    print("  sudo malloc-aggregation.d -c ./new-binary > /tmp/new")
+    print("  # diff them")
+    print("  stackdiff-dtrace.py /tmp/old /tmp/new")
+
+if len(sys.argv) != 3:
+    usage()
+    sys.exit(1)
+
+before_file = sys.argv[1]
+after_file = sys.argv[2]
+
+after_dict = put_in_dict(before_file)
+before_dict = put_in_dict(after_file)
+
+useful_after_keys = extract_useful_keys(after_dict)
+useful_before_keys = extract_useful_keys(before_dict)
+
+print("")
+print("### only in AFTER")
+for x in sorted(list(useful_after_keys - useful_before_keys)):
+    print(after_dict[x][0])
+    print(after_dict[x][1])
+
+print("")
+print("### only in BEFORE")
+for x in sorted(list(useful_before_keys - useful_after_keys)):
+    print(before_dict[x][0])
+    print(before_dict[x][1])
+
+print("")
+print("### different numbers")
+for x in sorted(list(useful_before_keys & useful_after_keys)):
+    if after_dict[x][0] != before_dict[x][0]:
+        print("before: %d, after: %d" % (before_dict[x][0],
+                                         after_dict[x][0]))
+        print(after_dict[x][1])

scripts/sanity.sh

@@ -36,7 +36,7 @@ fi
 printf "=> Checking license headers... "
 tmp=$(mktemp /tmp/.swift-nio-sanity_XXXXXX)
 
-for language in swift-or-c bash dtrace; do
+for language in swift-or-c bash dtrace python; do
   declare -a matching_files
   declare -a exceptions
   expections=( )
@@ -78,6 +78,25 @@ EOF
 ## SPDX-License-Identifier: Apache-2.0
 ##
 ##===----------------------------------------------------------------------===##
+EOF
+      ;;
+      python)
+        matching_files=( -name '*.py' )
+        cat > "$tmp" <<"EOF"
+#!/usr/bin/env python
+##===----------------------------------------------------------------------===##
+##
+## This source file is part of the SwiftNIO open source project
+##
+## Copyright (c) YEARS Apple Inc. and the SwiftNIO project authors
+## Licensed under Apache License v2.0
+##
+## See LICENSE.txt for license information
+## See CONTRIBUTORS.txt for the list of SwiftNIO project authors
+##
+## SPDX-License-Identifier: Apache-2.0
+##
+##===----------------------------------------------------------------------===##
 EOF
       ;;
       dtrace)