Function test_thread_switch

thread/test/test.cpp:347–377

int DevNull(void*, int);
void test_thread_switch(uint64_t nth, uint64_t stack_size)
{
    const uint64_t total = 100*1000*1000;
    uint64_t count = total / nth;

    for (uint64_t i = 0; i < nth - 2; ++i)
        photon::thread_create(&thread_pong, (void*)(uint64_t)(rand() % 32), stack_size);

    for (uint64_t i = 0; i < count; ++i)
        thread_yield_fast();

    auto t0 = now_time();
    for (uint64_t i = 0; i < count; ++i)
        thread_yield_fast();

    auto t1 = now_time();

    for (uint64_t i = 0; i < count; ++i)
        DevNull(&i, 0);

    auto t2 = now_time();

    auto d1 = t1 - t0;
    auto d2 = (t2 - t1) * nth;
    LOG_INFO("threads `, stack-size `, time `, loop time `, ", nth, stack_size, d1, d2);
    LOG_INFO("single context switch: ` ns (` M/s)",
             double((d1 - d2)*1000) / total, total / double(d1 - d2));

    running = 0;
    wait_for_completion();
}

TEST(Perf, ThreadSwitch)
{