Speed up simpleperf address matching

Currently, it takes 120 seconds for 2,000 Hz sampling,
and it takes more than 5 minutes for 10,000 Hz sampling.

This is slow because of the use of double loops. This can be avoided by
using a hashmap (dict) and a single loop with a more lenient pattern
matching. (ntfschr@'s idea)

With this change, the address matching part takes < 1 second.

Also, this adds some more logging to understand what is going on, and
adds a test case around the address that was not recognized.

Test: run_simpleperf_test covers this
Test: output result looks correct.
Bug: 1048428
Change-Id: I795c83133baeb07f8b78342d94e6d3b227eebd61
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2063811
Commit-Queue: Changwan Ryu <changwan@chromium.org>
Reviewed-by: Nate Fischer <ntfschr@chromium.org>
Reviewed-by: Oksana Zhuravlova <oksamyt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#743196}

android_webview/tools/run_simpleperf.py

@@ -98,6 +98,9 @@ class StackAddressInterpreter(object):
       for i in range(max(10, len(stack_output))):
         logging.debug(stack_output[i])
 
+    logging.info('We got the results from the stack script. Translating the '
+                 'addresses...')
+
     address_function_pairs = []
     pattern = re.compile(r'  0*(?P<address>[1-9a-f][0-9a-f]+)  (?P<function>.*)'
                          r'  (?P<file_name_line>.*)')
@@ -109,6 +112,8 @@ class StackAddressInterpreter(object):
           function_info += " | " + m.group('file_name_line')
 
         address_function_pairs.append((m.group('address'), function_info))
+
+    logging.info('The translation is done.')
     return address_function_pairs
 
 
@@ -164,6 +169,7 @@ class SimplePerfRunner(object):
     logging.info("Extracted %d addresses", len(addresses))
     address_function_pairs = self.address_interpreter.Interpret(
         addresses, lib_path)
+
     lines = SimplePerfRunner.ReplaceAddressesWithFunctionInfos(
         lines, address_function_pairs, lib_name)
 
@@ -254,14 +260,31 @@ class SimplePerfRunner(object):
       A list of strings with addresses replaced by function names.
     """
 
-    address_count = 0
-    for address, function in address_function_pairs:
-      pattern = re.compile(lib_name + r'\[\+' + address + r'\]')
-      for i, line in enumerate(lines):
-        address_count += len(pattern.findall(line))
-        lines[i] = pattern.sub(
-            lib_name + '[' + cgi.escape(function) + ']', line)
-    logging.info('There were %d matching addresses', address_count)
+    logging.info('Replacing the HTML content with new function names...')
+
+    # Note: Using a lenient pattern matching and a hashmap (dict) is much faster
+    # than using a double loop (by the order of 1,000).
+    # '+address' will be replaced by function name.
+    address_function_dict = {
+        '+' + k: cgi.escape(v)
+        for k, v in address_function_pairs
+    }
+    # Look behind the lib_name and '[' which will not be substituted. Note that
+    # '+' is used in the pattern but will be removed.
+    pattern = re.compile(r'(?<=' + lib_name + r'\[)\+([a-f0-9]+)(?=\])')
+
+    def replace_fn(match):
+      address = match.group(0)
+      if address in address_function_dict:
+        return address_function_dict[address]
+      else:
+        return address
+
+    # Line-by-line assignment to avoid creating a temp list.
+    for i, line in enumerate(lines):
+      lines[i] = pattern.sub(replace_fn, line)
+
+    logging.info('Replacing is done.')
     return lines
 
 

android_webview/tools/run_simpleperf_test.py

@@ -70,9 +70,11 @@ _EXAMPLE_INTERPRETER_OUTPUT_WITH_FILE_NAME_LINE = [
 
 _MOCK_ORIGINAL_REPORT = [
     '"442": {"l": 28, "f": "libwebviewchromium.so[+3db7d84]"},',
-    '"443": {"l": 28, "f": "libwebviewchromium.so[+3db7a5c]"},']
+    '"443": {"l": 28, "f": "libwebviewchromium.so[+3db7a5c]"},',
+    '"444": {"l": 28, "f": "libwebviewchromium.so[+aaaaaaa]"},'
+]
 
-_MOCK_ADDRESSES = ['3db7d84', '3db7a5c']
+_MOCK_ADDRESSES = ['3db7d84', '3db7a5c', 'aaaaaaa']
 
 _MOCK_ADDRESS_FUNCTION_NAME_PAIRS = [
     ('3db7d84', 'MyClass::FirstMethod(const char*)'),
@@ -82,7 +84,9 @@ _MOCK_FINAL_REPORT = [
     ('"442": {"l": 28, "f": "libwebviewchromium.so[MyClass::'
      'FirstMethod(const char*)]"},'),
     ('"443": {"l": 28, "f": "libwebviewchromium.so[MyClass::'
-     'SecondMethod(int)]"},')]
+     'SecondMethod(int)]"},'),
+    ('"444": {"l": 28, "f": "libwebviewchromium.so[+aaaaaaa]"},')
+]
 
 
 class _RunSimpleperfTest(unittest.TestCase):