blob: b2c4a9ac525db4fbdd6c960983c20637b45fee5c (
plain)
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
|
/*
* Copyright (C) 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef SRC_TRACED_PROBES_FTRACE_FTRACE_THREAD_SYNC_H_
#define SRC_TRACED_PROBES_FTRACE_FTRACE_THREAD_SYNC_H_
#include <stdint.h>
#include <bitset>
#include <condition_variable>
#include <mutex>
#include "perfetto/base/utils.h"
#include "perfetto/base/weak_ptr.h"
namespace perfetto {
namespace base {
class TaskRunner;
} // namespace base
class FtraceController;
// This struct is accessed both by the FtraceController on the main thread and
// by the CpuReader(s) on their worker threads. It is used to synchronize
// handshakes between FtraceController and CpuReader(s). There is only *ONE*
// instance of this state, owned by the FtraceController and shared with all
// CpuReader(s).
struct FtraceThreadSync {
explicit FtraceThreadSync(base::TaskRunner* tr) : task_runner(tr) {}
// These variables are set upon initialization time and never changed. Can
// be accessed outside of the |mutex|.
base::TaskRunner* const task_runner; // Where the FtraceController lives.
base::WeakPtr<FtraceController> trace_controller_weak;
// Mutex & condition variable shared by main thread and all per-cpu workers.
// All fields below are read and modified holding |mutex|.
std::mutex mutex;
// Used to suspend CpuReader(s) between cycles and to wake them up at the
// same time.
std::condition_variable cond;
// |cmd| and |cmd_id| are written only by FtraceController. On each cycle,
// FtraceController increases the |cmd_id| monotonic counter and issues the
// new command. |cmd_id| is used by the CpuReader(s) to distinguish a new
// command from a spurious wakeup.
enum Cmd { kRun = 0, kFlush, kQuit };
Cmd cmd = kRun;
uint64_t cmd_id = 0;
// This bitmap is cleared by the FtraceController before every kRun command
// and is optionally set by OnDataAvailable() if a CpuReader did fetch any
// ftrace data during the read cycle.
std::bitset<base::kMaxCpus> cpus_to_drain;
// This bitmap is cleared by the FtraceController before issuing a kFlush
// command and set by each CpuReader after they have completed the flush.
std::bitset<base::kMaxCpus> flush_acks;
};
} // namespace perfetto
#endif // SRC_TRACED_PROBES_FTRACE_FTRACE_THREAD_SYNC_H_
|
