Add a sampling profiler and a script to generate profiles for use with Gecko tooling.

etc/profilicate.py

@@ -0,0 +1,153 @@
+#!/usr/bin/env python
+
+# Copyright 2018 The Servo Project Developers. See the COPYRIGHT
+# file at the top-level directory of this distribution.
+#
+# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+# option. This file may not be copied, modified, or distributed
+# except according to those terms.
+
+# Script to take raw sample output from Servo sampling profiler and
+# output a [processed profile]. Based largely on [this script] and
+# [this documentation].
+#
+# [processed profile]: https://github.com/firefox-devtools/profiler/blob/master/docs-developer/processed-profile-format.md
+# [this script]: https://github.com/firefox-devtools/profiler/blob/master/src/profile-logic/import/linux-perf.js
+# [this documentation]: https://github.com/firefox-devtools/profiler/blob/master/src/types/profile.js
+
+from collections import defaultdict
+import json
+import sys
+
+
+class StringTable:
+    def __init__(self):
+        self.table = {}
+        self.idx = 0
+
+    def get(self, s):
+        assert s
+        if s not in self.table:
+            self.table[s] = self.idx
+            self.idx += 1
+        return self.table[s]
+
+    def length(self):
+        return len(self.table.keys())
+
+    def contents(self):
+        return sorted(self.table.keys(), key=self.table.__getitem__)
+
+
+with open(sys.argv[1]) as f:
+    profile = json.load(f)
+    rate = profile["rate"]
+    samples = profile["data"]
+    startTime = profile["start"]
+
+frames = {}
+stacks = {}
+
+thread_data = defaultdict(list)
+thread_order = {}
+for sample in samples:
+    if sample['name']:
+        name = sample['name']
+    else:
+        name = "%s %d %d" % (sample['type'], sample['namespace'], sample['index'])
+    thread_data[name].append((sample['time'], sample['frames']))
+    if name not in thread_order:
+        thread_order[name] = (sample['namespace'], sample['index'])
+
+tid = 0
+threads = []
+for (name, raw_samples) in sorted(thread_data.iteritems(), key=lambda x: thread_order[x[0]]):
+    string_table = StringTable()
+    tid += 1
+
+    stackMap = {}
+    stacks = []
+    frameMap = {}
+    frames = []
+
+    samples = []
+
+    for sample in raw_samples:
+        prefix = None
+        for frame in sample[1]:
+            if not frame['name']:
+                continue
+            if not frame['name'] in frameMap:
+                frameMap[frame['name']] = len(frames)
+                frame_index = string_table.get(frame['name'])
+                frames.append([frame_index])
+            frame = frameMap[frame['name']]
+
+            stack_key = "%d,%d" % (frame, prefix) if prefix else str(frame)
+            if stack_key not in stackMap:
+                stackMap[stack_key] = len(stacks)
+                stacks.append([frame, prefix])
+            stack = stackMap[stack_key]
+            prefix = stack
+        samples.append([stack, sample[0]])
+
+    threads.append({
+        'tid': tid,
+        'name': name,
+        'markers': {
+            'schema': {
+                'name': 0,
+                'time': 1,
+                'data': 2,
+            },
+            'data': [],
+        },
+        'samples': {
+            'schema': {
+                'stack': 0,
+                'time': 1,
+                'responsiveness': 2,
+                'rss': 2,
+                'uss': 4,
+                'frameNumber': 5,
+            },
+            'data': samples,
+        },
+        'frameTable': {
+            'schema': {
+                'location': 0,
+                'implementation': 1,
+                'optimizations': 2,
+                'line': 3,
+                'category': 4,
+            },
+            'data': frames,
+        },
+        'stackTable': {
+            'schema': {
+                'frame': 0,
+                'prefix': 1,
+            },
+            'data': stacks,
+        },
+        'stringTable': string_table.contents(),
+    })
+
+
+output = {
+    'meta': {
+        'interval': rate,
+        'processType': 0,
+        'product': 'Servo',
+        'stackwalk': 1,
+        'startTime': startTime,
+        'version': 4,
+        'presymbolicated': True,
+    },
+    'libs': [],
+    'threads': threads,
+}
+
+print(json.dumps(output))