mesytec-mnode/external/taskflow-3.8.0/examples/pipeline_with_deferred_tokens.cpp
2025-01-04 01:25:05 +01:00

121 lines
3.2 KiB
C++

// This program demonstrates how to create a pipeline scheduling framework
// that defers the exection of current scheuling token to the future.
//
// The pipeline has the following structure:
//
// o -> o -> o
// | | |
// v v v
// o -> o -> o
// | | |
// v v v
// o -> o -> o
// | | |
// v v v
// o -> o -> o
// The scheduling token has the following dependencies:
// ___________
// | |
// V _____ |
// | | |
// | V |
// 1 2 3 4 5 6 7 8 9 10
// ^ | |
// |___| |
// ^ |
// |_______|
//
// 2 is deferred by 8
// 5 is dieferred by 2, 7, and 9
#include <taskflow/taskflow.hpp>
#include <taskflow/algorithm/pipeline.hpp>
int main() {
tf::Taskflow taskflow("deferred_pipeline");
tf::Executor executor;
const size_t num_lines = 4;
// the pipeline consists of three pipes (serial-parallel-serial)
// and up to four concurrent scheduling tokens
tf::Pipeline pl(num_lines,
tf::Pipe{tf::PipeType::SERIAL, [](tf::Pipeflow& pf) {
// generate only 15 scheduling tokens
if(pf.token() == 15) {
pf.stop();
}
else {
// Token 5 is deferred
if (pf.token() == 5) {
switch(pf.num_deferrals()) {
case 0:
pf.defer(2);
printf("1st-time: Token %zu is deferred by 2\n", pf.token());
pf.defer(7);
printf("1st-time: Token %zu is deferred by 7\n", pf.token());
return;
break;
case 1:
pf.defer(9);
printf("2nd-time: Token %zu is deferred by 9\n", pf.token());
return;
break;
case 2:
printf("3rd-time: Tokens 2, 7 and 9 resolved dependencies for token %zu\n", pf.token());
break;
}
}
else if (pf.token() == 2) {
switch(pf.num_deferrals()) {
case 0:
pf.defer(8);
printf("1st-time: Token %zu is deferred by 8\n", pf.token());
break;
case 1:
printf("2nd-time: Token 8 resolved dependencies for token %zu\n", pf.token());
break;
}
}
else {
printf("stage 1: Non-deferred token %zu\n", pf.token());
}
}
}},
tf::Pipe{tf::PipeType::SERIAL, [](tf::Pipeflow& pf) {
printf("stage 2: input token %zu (deferrals=%zu)\n", pf.token(), pf.num_deferrals());
}},
tf::Pipe{tf::PipeType::SERIAL, [](tf::Pipeflow& pf) {
printf("stage 3: input token %zu\n", pf.token());
}}
);
// build the pipeline graph using composition
tf::Task init = taskflow.emplace([](){ std::cout << "ready\n"; })
.name("starting pipeline");
tf::Task task = taskflow.composed_of(pl)
.name("deferred_pipeline");
tf::Task stop = taskflow.emplace([](){ std::cout << "stopped\n"; })
.name("pipeline stopped");
// create task dependency
init.precede(task);
task.precede(stop);
// dump the pipeline graph structure (with composition)
taskflow.dump(std::cout);
// run the pipeline
executor.run(taskflow).wait();
return 0;
}