source: doc/theses/thierry_delisle_PhD/code/relaxed_list.cpp @ b2a37b0

#include "relaxed_list.hpp"

#include <array>
#include <iostream>
#include <locale>
#include <string>
#include <thread>
#include <vector>

#include <unistd.h>
#include <sys/sysinfo.h>

#include "utils.hpp"

struct Node {
        static std::atomic_size_t creates;
        static std::atomic_size_t destroys;

        _LinksFields_t<Node> _links;

        int value;
        Node(int value): value(value) {
                creates++;
        }

        ~Node() {
                destroys++;
        }
};

std::atomic_size_t Node::creates  = { 0 };
std::atomic_size_t Node::destroys = { 0 };

static const constexpr int nodes_per_threads = 128;

bool enable_stats = false;

__attribute__((aligned(64))) thread_local pick_stat local_pick;

void run(unsigned nthread, double duration) {
        // List being tested
        relaxed_list<Node> list = { nthread * 2 };

        // Barrier for synchronization
        barrier_t barrier(nthread + 1);

        // Data to check everything is OK
        struct {
                std::atomic_size_t in  = { 0 };
                std::atomic_size_t out = { 0 };
                std::atomic_size_t empty = { 0 };
                std::atomic_size_t crc_in  = { 0 };
                std::atomic_size_t crc_out = { 0 };
                std::atomic_size_t pick_at = { 0 };
                std::atomic_size_t pick_su = { 0 };
        } global;

        // Flag to signal termination
        std::atomic_bool done  = { false };

        // Prep nodes
        std::cout << "Initializing" << std::endl;
        std::vector<Node *> all_nodes[nthread];
        for(auto & nodes : all_nodes) {
                Random rand(rdtscl());
                nodes.resize(nodes_per_threads);
                for(auto & node : nodes) {
                        node = new Node(rand.next() % 100);
                }

                for(int i = 0; i < 10; i++) {
                        int idx = rand.next() % nodes_per_threads;
                        if (auto node = nodes[idx]) {
                                global.crc_in += node->value;
                                list.push(node);
                                nodes[idx] = nullptr;
                        }
                }
        }

        enable_stats = true;

        std::thread * threads[nthread];
        unsigned i = 1;
        for(auto & t : threads) {
                auto & my_nodes = all_nodes[i - 1];
                t = new std::thread([&done, &list, &barrier, &global, &my_nodes](unsigned tid) {
                        Random rand(tid + rdtscl());

                        size_t local_in  = 0;
                        size_t local_out = 0;
                        size_t local_empty = 0;
                        size_t local_crc_in  = 0;
                        size_t local_crc_out = 0;

                        affinity(tid);

                        barrier.wait(tid);

                        // EXPERIMENT START

                        while(__builtin_expect(!done, true)) {
                                int idx = rand.next() % nodes_per_threads;
                                if (auto node = my_nodes[idx]) {
                                        local_crc_in += node->value;
                                        list.push(node);
                                        my_nodes[idx] = nullptr;
                                        local_in++;
                                }
                                else if(auto node = list.pop2()) {
                                        local_crc_out += node->value;
                                        my_nodes[idx] = node;
                                        local_out++;
                                }
                                else {
                                        local_empty++;
                                }
                        }

                        // EXPERIMENT END

                        barrier.wait(tid);

                        global.in    += local_in;
                        global.out   += local_out;
                        global.empty += local_empty;

                        for(auto node : my_nodes) {
                                delete node;
                        }

                        global.crc_in  += local_crc_in;
                        global.crc_out += local_crc_out;

                        global.pick_at += local_pick.attempt;
                        global.pick_su += local_pick.success;
                }, i++);
        }

        std::cout << "Starting" << std::endl;
        auto before = Clock::now();
        barrier.wait(0);

        while(true) {
                usleep(1000);
                auto now = Clock::now();
                duration_t durr = now - before;
                if( durr.count() > duration ) {
                        done = true;
                        break;
                }
        }

        barrier.wait(0);
        auto after = Clock::now();
        duration_t durr = after - before;
        duration = durr.count();
        std::cout << "Closing down" << std::endl;

        for(auto t : threads) {
                t->join();
                delete t;
        }

        enable_stats = false;

        while(auto node = list.pop()) {
                global.crc_out += node->value;
                delete node;
        }

        assert(Node::creates == Node::destroys);
        assert(global.crc_in == global.crc_out);

        std::cout << "Done" << std::endl;

        size_t ops = global.in + global.out;
        size_t ops_sec = size_t(double(ops) / duration);
        size_t ops_thread = ops_sec / nthread;
        auto dur_nano = duration_cast<std::nano>(1.0);

        std::cout << "Duration      : " << duration << "s\n";
        std::cout << "Total ops     : " << ops << "(" << global.in << "i, " << global.out << "o, " << global.empty << "e)\n";
        std::cout << "Ops/sec       : " << ops_sec << "\n";
        std::cout << "Ops/sec/thread: " << ops_thread << "\n";
        std::cout << "ns/Op         : " << ( dur_nano / ops_thread )<< "\n";
        std::cout << "Pick %        : " << (100.0 * double(global.pick_su) / global.pick_at) << "(" << global.pick_su << " / " << global.pick_at << ")\n";
}

void usage(char * argv[]) {
        std::cerr << argv[0] << ": [DURATION (FLOAT:SEC)] [NTHREADS]" << std::endl;;
        std::exit(1);
}

int main(int argc, char * argv[]) {

        double duration   = 5.0;
        unsigned nthreads = 2;

        std::cout.imbue(std::locale(""));

        switch (argc)
        {
        case 3:
                nthreads = std::stoul(argv[2]);
                [[fallthrough]];
        case 2:
                duration = std::stod(argv[1]);
                if( duration <= 0.0 ) {
                        std::cerr << "Duration must be positive, was " << argv[1] << "(" << duration << ")" << std::endl;
                        usage(argv);
                }
                [[fallthrough]];
        case 1:
                break;
        default:
                usage(argv);
                break;
        }

        check_cache_line_size();

        std::cout << "Running " << nthreads << " threads for " << duration << " seconds" << std::endl;
        run(nthreads, duration);

        return 0;
}

template<>
thread_local Random relaxed_list<Node>::rng_g = { int(rdtscl()) };