1 // Copyright 2020 The Pigweed Authors
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not
4 // use this file except in compliance with the License. You may obtain a copy of
5 // the License at
6 //
7 // https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12 // License for the specific language governing permissions and limitations under
13 // the License.
14 //==============================================================================
15 // ninja -C out/host trace_sample
16 // ./out/host/obj/pw_trace_tokenized/trace_sample
17 // python pw_trace_tokenized/py/trace.py -i out1.bin -o trace.json
18 // ./out/host/obj/pw_trace_tokenized/trace_sample
19 #include <stdio.h>
20
21 #include <array>
22 #include <chrono>
23
24 #include "pw_ring_buffer/prefixed_entry_ring_buffer.h"
25 #include "pw_trace/trace.h"
26
27 #ifndef SAMPLE_APP_SLEEP_MILLIS
28 #include <thread>
29 #define SAMPLE_APP_SLEEP_MILLIS(millis) \
30 std::this_thread::sleep_for(std::chrono::milliseconds(millis));
31 #endif // SAMPLE_APP_SLEEP_MILLIS
32
33 using namespace std::chrono;
34
35 namespace {
36
37 // Time helper function
38 auto start = system_clock::now();
GetTimeSinceBootMillis()39 uint32_t GetTimeSinceBootMillis() {
40 auto delta = system_clock::now() - start;
41 return floor<milliseconds>(delta).count();
42 }
43
44 // Creating a very simple runnable with predictable behaviour to help with the
45 // example. Each Runnable, has a method ShouldRun which indicates if it has work
46 // to do, calling Run will then do the work.
47 class SimpleRunnable {
48 public:
49 virtual const char* Name() const = 0;
50 virtual bool ShouldRun() = 0;
51 virtual void Run() = 0;
~SimpleRunnable()52 virtual ~SimpleRunnable() {}
53 };
54
55 // Processing module
56 // Uses trace_id and groups to track the multiple stages of "processing".
57 // These are intentionally long running so they will be processing concurrently.
58 // The trace ID is used to seperates these concurrent jobs.
59 #undef PW_TRACE_MODULE_NAME
60 #define PW_TRACE_MODULE_NAME "Processing"
61 class ProcessingTask : public SimpleRunnable {
62 public:
63 // Run task maintains a buffer of "jobs" which just sleeps for an amount of
64 // time and reposts the job until the value is zero. This gives an async
65 // behaviour where multiple of the same job are happening concurrently, and
66 // also has a nesting effect of a job having many stages.
67 struct Job {
68 uint32_t job_id;
69 uint8_t value;
70 };
71 struct JobBytes {
72 union {
73 Job job;
74 std::byte bytes[sizeof(Job)];
75 };
76 };
ProcessingTask()77 ProcessingTask() {
78 // Buffer is used for the job queue.
79 std::span<std::byte> buf_span = std::span<std::byte>(
80 reinterpret_cast<std::byte*>(jobs_buffer_), sizeof(jobs_buffer_));
81 jobs_.SetBuffer(buf_span);
82 }
Name() const83 const char* Name() const override { return "Processing Task"; }
ShouldRun()84 bool ShouldRun() override { return jobs_.EntryCount() > 0; }
Run()85 void Run() override {
86 JobBytes job_bytes;
87 size_t bytes_read;
88
89 // Trace the job count backlog
90 size_t entry_count = jobs_.EntryCount();
91
92 // Get the next job from the queue.
93 jobs_.PeekFront(job_bytes.bytes, &bytes_read);
94 jobs_.PopFront();
95 Job& job = job_bytes.job;
96
97 // Process the job
98 ProcessingJob(job);
99 if (job.value > 0) { // repost for more work if value > 0
100 AddJobInternal(job.job_id, job.value - 1);
101 } else {
102 PW_TRACE_END("Job", "Process", job.job_id);
103 }
104 PW_TRACE_INSTANT_DATA("job_backlog_count",
105 "@pw_arg_counter",
106 &entry_count,
107 sizeof(entry_count));
108 }
AddJob(uint32_t job_id,uint8_t value)109 void AddJob(uint32_t job_id, uint8_t value) {
110 PW_TRACE_START_DATA(
111 "Job", "Process", job_id, "@pw_py_struct_fmt:B", &value, sizeof(value));
112 AddJobInternal(job_id, value);
113 }
114
115 private:
116 static constexpr size_t kMaxJobs = 10;
117 static constexpr size_t kProcessingTimePerValueMillis = 250;
118 Job jobs_buffer_[kMaxJobs];
119 pw::ring_buffer::PrefixedEntryRingBuffer jobs_{false};
120
ProcessingJob(const Job & job)121 void ProcessingJob(const Job& job) {
122 PW_TRACE_FUNCTION("Process", job.job_id);
123 for (uint8_t i = 0; i < job.value; i++) {
124 PW_TRACE_SCOPE("loop", "Process", job.job_id);
125 SAMPLE_APP_SLEEP_MILLIS(50); // Fake processing time
126 SomeProcessing(&job);
127 }
128 }
129
SomeProcessing(const Job * job)130 void SomeProcessing(const Job* job) {
131 uint32_t id = job->job_id;
132 PW_TRACE_FUNCTION("Process", id);
133 SAMPLE_APP_SLEEP_MILLIS(
134 kProcessingTimePerValueMillis); // Fake processing time
135 }
AddJobInternal(uint32_t job_id,uint8_t value)136 void AddJobInternal(uint32_t job_id, uint8_t value) {
137 JobBytes job{.job = {.job_id = job_id, .value = value}};
138 jobs_.PushBack(job.bytes);
139 }
140 } processing_task;
141
142 // Input Module
143 // Uses traces in groups to indicate the different steps of reading the new
144 // event.
145 // Uses an instant data event to dump the read sample into the trace.
146 #undef PW_TRACE_MODULE_NAME
147 #define PW_TRACE_MODULE_NAME "Input"
148 class InputTask : public SimpleRunnable {
149 // Every second generate new output
150 public:
Name() const151 const char* Name() const override { return "Input Task"; }
ShouldRun()152 bool ShouldRun() override {
153 return (GetTimeSinceBootMillis() - last_run_time_ > kRunInterval);
154 }
Run()155 void Run() override {
156 last_run_time_ = GetTimeSinceBootMillis();
157 PW_TRACE_FUNCTION("Input");
158 SAMPLE_APP_SLEEP_MILLIS(50);
159 uint8_t value = GetValue();
160 PW_TRACE_INSTANT_DATA("value", "@pw_arg_counter", &value, sizeof(value));
161 processing_task.AddJob(sample_count_, value);
162 sample_count_++;
163 }
164
165 private:
GetValue()166 uint8_t GetValue() {
167 PW_TRACE_FUNCTION("Input");
168 SAMPLE_APP_SLEEP_MILLIS(100); // Fake processing time
169 return sample_count_ % 4 + 1;
170 }
171 size_t sample_count_ = 0;
172 uint32_t last_run_time_ = 0;
173 static constexpr uint32_t kRunInterval = 1000;
174 } input_task;
175
176 // Simple main loop acting as the "Kernel"
177 // Uses simple named trace durations to indicate which task/job is running
178 #undef PW_TRACE_MODULE_NAME
179 #define PW_TRACE_MODULE_NAME "Kernel"
StartFakeKernel()180 void StartFakeKernel() {
181 std::array<SimpleRunnable*, 2> tasks = {&input_task, &processing_task};
182
183 bool idle = false;
184 while (true) {
185 bool have_any_run = false;
186 for (auto& task : tasks) {
187 if (task->ShouldRun()) {
188 if (idle) {
189 PW_TRACE_END("Idle", "Idle");
190 idle = false;
191 }
192 have_any_run = true;
193 // The task name is not a string literal and is therefore put in the
194 // data section, so it can also work with tokenized trace.
195 PW_TRACE_START_DATA(
196 "Running", "@pw_arg_group", task->Name(), strlen(task->Name()));
197 task->Run();
198 PW_TRACE_END_DATA(
199 "Running", "@pw_arg_group", task->Name(), strlen(task->Name()));
200 }
201 }
202 if (!idle && !have_any_run) {
203 PW_TRACE_START("Idle", "Idle");
204 idle = true;
205 }
206 }
207 }
208
209 } // namespace
210
RunTraceSampleApp()211 void RunTraceSampleApp() { StartFakeKernel(); }
212