1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CHROME_BROWSER_METRICS_TRACKING_SYNCHRONIZER_H_
#define CHROME_BROWSER_METRICS_TRACKING_SYNCHRONIZER_H_
#pragma once
#include <map>
#include <string>
#include <vector>
#include "base/basictypes.h"
#include "base/lazy_instance.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/values.h"
#include "chrome/browser/ui/webui/profiler_ui.h"
#include "content/public/browser/profiler_subscriber.h"
// This class maintains state that is used to upload profiler data from the
// various processes, into the browser process. Such transactions are usually
// instigated by the browser. In general, a process will respond by gathering
// profiler data, and transmitting the pickled profiler data. We collect the
// data in asynchronous mode that doesn't block the UI thread.
//
// To assure that all the processes have responded, a counter is maintained
// to indicate the number of pending (not yet responsive) processes. We tag
// each group of requests with a sequence number. For each group of requests, we
// create RequestContext object which stores the sequence number, pending
// processes and the callback_object that needs to be notified when we receive
// an update from processes. When an update arrives we find the RequestContext
// associated with sequence number and send the unpickled profiler data to the
// |callback_object_|.
namespace chrome_browser_metrics {
class RequestContext;
class TrackingSynchronizer
: public content::ProfilerSubscriber,
public base::RefCountedThreadSafe<TrackingSynchronizer> {
public:
// Construction also sets up the global singleton instance. This instance is
// used to communicate between the IO and UI thread, and is destroyed only as
// the main thread (browser_main) terminates, which means the IO thread has
// already completed, and will not need this instance any further.
TrackingSynchronizer();
// Contact all processes, and get them to upload to the browser any/all
// changes to profiler data. It calls |callback_object|'s SetData method with
// the data received from each sub-process.
// This method is accessible on UI thread.
static void FetchProfilerDataAsynchronously(
const base::WeakPtr<ProfilerUI>& callback_object);
// ------------------------------------------------------
// ProfilerSubscriber methods for browser child processes
// ------------------------------------------------------
// Update the number of pending processes for the given |sequence_number|.
// This is called on UI thread.
virtual void OnPendingProcesses(int sequence_number,
int pending_processes,
bool end) OVERRIDE;
// Send profiler_data back to callback_object_ by calling
// DecrementPendingProcessesAndSendData which records that we are waiting
// for one less profiler data from renderer or browser child process for the
// given sequence number. This method is accessible on UI thread.
virtual void OnProfilerDataCollected(
int sequence_number,
base::DictionaryValue* profiler_data) OVERRIDE;
private:
friend class base::RefCountedThreadSafe<TrackingSynchronizer>;
friend class RequestContext;
virtual ~TrackingSynchronizer();
// Send profiler_data back to callback_object_. It records that we are waiting
// for one less profiler data from renderer or browser child process for the
// given sequence number. This method is accessible on UI thread.
void OnProfilerDataCollectedOnUI(int sequence_number,
base::DictionaryValue* profiler_data);
// Establish a new sequence_number_, and use it to notify all the processes of
// the need to supply, to the browser, their tracking data. It also registers
// |callback_object| in |outstanding_requests_| map. Return the
// sequence_number_ that was used. This method is accessible on UI thread.
int RegisterAndNotifyAllProcesses(
const base::WeakPtr<ProfilerUI>& callback_object);
// It finds the RequestContext for the given |sequence_number| and notifies
// the RequestContext's |callback_object_| about the |value|. This is called
// whenever we receive profiler data from processes. It also records that we
// are waiting for one less profiler data from a process for the given
// sequence number. If we have received a response from all renderers and
// browser processes, then it calls RequestContext's DeleteIfAllDone to delete
// the entry for sequence_number. This method is accessible on UI thread.
void DecrementPendingProcessesAndSendData(int sequence_number,
base::DictionaryValue* value);
// Get a new sequence number to be sent to processes from browser process.
// This method is accessible on UI thread.
int GetNextAvailableSequenceNumber();
// Return pointer to the singleton instance, which is allocated and
// deallocated on the main UI thread (during system startup and teardown).
// This method is accessible on UI thread.
static TrackingSynchronizer* CurrentSynchronizer();
// We don't track the actual processes that are contacted for an update, only
// the count of the number of processes, and we can sometimes time-out and
// give up on a "slow to respond" process. We use a sequence_number to be
// sure a response from a process is associated with the current round of
// requests. All sequence numbers used are non-negative.
// last_used_sequence_number_ is the most recently used number (used to avoid
// reuse for a long time).
int last_used_sequence_number_;
// This singleton instance should be started during the single threaded
// portion of main(). It initializes globals to provide support for all future
// calls. This object is created on the UI thread, and it is destroyed after
// all the other threads have gone away. As a result, it is ok to call it
// from the UI thread, or for about:profiler.
static TrackingSynchronizer* tracking_synchronizer_;
DISALLOW_COPY_AND_ASSIGN(TrackingSynchronizer);
};
} // namespace chrome_browser_metrics
#endif // CHROME_BROWSER_METRICS_TRACKING_SYNCHRONIZER_H_
|
