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// Copyright 2020 The Pigweed Authors
//
// 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
//
// https://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.
//==============================================================================
// ninja -C out/host trace_sample
// ./out/host/obj/pw_trace_tokenized/trace_sample
// python pw_trace_tokenized/py/trace.py -i out1.bin -o trace.json
// ./out/host/obj/pw_trace_tokenized/trace_sample
#include <stdio.h>
#include <array>
#include <chrono>
#include "pw_ring_buffer/prefixed_entry_ring_buffer.h"
#include "pw_trace/trace.h"
#ifndef SAMPLE_APP_SLEEP_MILLIS
#include <thread>
#define SAMPLE_APP_SLEEP_MILLIS(millis) \
std::this_thread::sleep_for(std::chrono::milliseconds(millis));
#endif // SAMPLE_APP_SLEEP_MILLIS
using namespace std::chrono;
namespace {
// Time helper function
auto start = system_clock::now();
uint32_t GetTimeSinceBootMillis() {
auto delta = system_clock::now() - start;
return floor<milliseconds>(delta).count();
}
// Creating a very simple runnable with predictable behaviour to help with the
// example. Each Runnable, has a method ShouldRun which indicates if it has work
// to do, calling Run will then do the work.
class SimpleRunnable {
public:
virtual const char* Name() const = 0;
virtual bool ShouldRun() = 0;
virtual void Run() = 0;
virtual ~SimpleRunnable() {}
};
// Processing module
// Uses trace_id and groups to track the multiple stages of "processing".
// These are intentionally long running so they will be processing concurrently.
// The trace ID is used to seperates these concurrent jobs.
#undef PW_TRACE_MODULE_NAME
#define PW_TRACE_MODULE_NAME "Processing"
class ProcessingTask : public SimpleRunnable {
public:
// Run task maintains a buffer of "jobs" which just sleeps for an amount of
// time and reposts the job until the value is zero. This gives an async
// behaviour where multiple of the same job are happening concurrently, and
// also has a nesting effect of a job having many stages.
struct Job {
uint32_t job_id;
uint8_t value;
};
struct JobBytes {
union {
Job job;
std::byte bytes[sizeof(Job)];
};
};
ProcessingTask() {
// Buffer is used for the job queue.
std::span<std::byte> buf_span = std::span<std::byte>(
reinterpret_cast<std::byte*>(jobs_buffer_), sizeof(jobs_buffer_));
jobs_.SetBuffer(buf_span)
.IgnoreError(); // TODO(pwbug/387): Handle Status properly
}
const char* Name() const override { return "Processing Task"; }
bool ShouldRun() override { return jobs_.EntryCount() > 0; }
void Run() override {
JobBytes job_bytes;
size_t bytes_read;
// Trace the job count backlog
size_t entry_count = jobs_.EntryCount();
// Get the next job from the queue.
jobs_.PeekFront(job_bytes.bytes, &bytes_read)
.IgnoreError(); // TODO(pwbug/387): Handle Status properly
jobs_.PopFront().IgnoreError(); // TODO(pwbug/387): Handle Status properly
Job& job = job_bytes.job;
// Process the job
ProcessingJob(job);
if (job.value > 0) { // repost for more work if value > 0
AddJobInternal(job.job_id, job.value - 1);
} else {
PW_TRACE_END("Job", "Process", job.job_id);
}
PW_TRACE_INSTANT_DATA("job_backlog_count",
"@pw_arg_counter",
&entry_count,
sizeof(entry_count));
}
void AddJob(uint32_t job_id, uint8_t value) {
PW_TRACE_START_DATA(
"Job", "Process", job_id, "@pw_py_struct_fmt:B", &value, sizeof(value));
AddJobInternal(job_id, value);
}
private:
static constexpr size_t kMaxJobs = 10;
static constexpr size_t kProcessingTimePerValueMillis = 250;
Job jobs_buffer_[kMaxJobs];
pw::ring_buffer::PrefixedEntryRingBuffer jobs_{false};
void ProcessingJob(const Job& job) {
PW_TRACE_FUNCTION("Process", job.job_id);
for (uint8_t i = 0; i < job.value; i++) {
PW_TRACE_SCOPE("loop", "Process", job.job_id);
SAMPLE_APP_SLEEP_MILLIS(50); // Fake processing time
SomeProcessing(&job);
}
}
void SomeProcessing(const Job* job) {
uint32_t id = job->job_id;
PW_TRACE_FUNCTION("Process", id);
SAMPLE_APP_SLEEP_MILLIS(
kProcessingTimePerValueMillis); // Fake processing time
}
void AddJobInternal(uint32_t job_id, uint8_t value) {
JobBytes job{.job = {.job_id = job_id, .value = value}};
jobs_.PushBack(job.bytes)
.IgnoreError(); // TODO(pwbug/387): Handle Status properly
}
} processing_task;
// Input Module
// Uses traces in groups to indicate the different steps of reading the new
// event.
// Uses an instant data event to dump the read sample into the trace.
#undef PW_TRACE_MODULE_NAME
#define PW_TRACE_MODULE_NAME "Input"
class InputTask : public SimpleRunnable {
// Every second generate new output
public:
const char* Name() const override { return "Input Task"; }
bool ShouldRun() override {
return (GetTimeSinceBootMillis() - last_run_time_ > kRunInterval);
}
void Run() override {
last_run_time_ = GetTimeSinceBootMillis();
PW_TRACE_FUNCTION("Input");
SAMPLE_APP_SLEEP_MILLIS(50);
uint8_t value = GetValue();
PW_TRACE_INSTANT_DATA("value", "@pw_arg_counter", &value, sizeof(value));
processing_task.AddJob(sample_count_, value);
sample_count_++;
}
private:
uint8_t GetValue() {
PW_TRACE_FUNCTION("Input");
SAMPLE_APP_SLEEP_MILLIS(100); // Fake processing time
return sample_count_ % 4 + 1;
}
size_t sample_count_ = 0;
uint32_t last_run_time_ = 0;
static constexpr uint32_t kRunInterval = 1000;
} input_task;
// Simple main loop acting as the "Kernel"
// Uses simple named trace durations to indicate which task/job is running
#undef PW_TRACE_MODULE_NAME
#define PW_TRACE_MODULE_NAME "Kernel"
void StartFakeKernel() {
std::array<SimpleRunnable*, 2> tasks = {&input_task, &processing_task};
bool idle = false;
while (true) {
bool have_any_run = false;
for (auto& task : tasks) {
if (task->ShouldRun()) {
if (idle) {
PW_TRACE_END("Idle", "Idle");
idle = false;
}
have_any_run = true;
// The task name is not a string literal and is therefore put in the
// data section, so it can also work with tokenized trace.
PW_TRACE_START_DATA(
"Running", "@pw_arg_group", task->Name(), strlen(task->Name()));
task->Run();
PW_TRACE_END_DATA(
"Running", "@pw_arg_group", task->Name(), strlen(task->Name()));
}
}
if (!idle && !have_any_run) {
PW_TRACE_START("Idle", "Idle");
idle = true;
}
}
}
} // namespace
void RunTraceSampleApp() { StartFakeKernel(); }