HelloAurora/Tests/Public/5. Hello Loop/Main.cpp

/***
    Copyright (C) 2022 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: Main.cpp
    Date: 2022-2-18
    Author: Reece
***/
#include <AuroraRuntime.hpp>
#include <gtest/gtest.h>

TEST(Loop, Semaphore)
{
    auto semaA = Aurora::Loop::NewLSSemaphore(1);
    auto semaB = Aurora::Loop::NewLSSemaphore(0);
    auto semac = Aurora::Loop::NewLSSemaphore(0);
    auto loop = Aurora::Loop::NewLoopQueue();
    
    // Add initial loop sources
    ASSERT_TRUE(loop->SourceAdd(semaA));
    ASSERT_TRUE(loop->SourceAdd(semaB));
    ASSERT_TRUE(loop->SourceAddWithTimeout(semac, 2000));


    auto semACallback = AuMakeShared<Aurora::Loop::ILoopSourceSubscriberFunctional>([](const AuSPtr<Aurora::Loop::ILoopSource> &source) -> bool
    {
        AuLogInfo("Hello from semaphore a's work queue");
        return false; // dont evict, we'll reuse this  *1 (search for me)
    });

    auto semBCallback = AuMakeShared<Aurora::Loop::ILoopSourceSubscriberFunctional>([](const AuSPtr<Aurora::Loop::ILoopSource> &source) -> bool
    {
        AuLogInfo("Hello from semaphore b's work queue");
        return true; // evict
    });


    auto semCCallback = AuMakeShared<Aurora::Loop::ILoopSourceSubscriberExFunctional>([](const AuSPtr<Aurora::Loop::ILoopSource> &source) -> bool
    {
        AuLogInfo("This should not have been triggered from C");
        return false;
    },

                                                                                      [](const AuSPtr<Aurora::Loop::ILoopSource> &source) -> void
    {
        AuLogInfo("C timedout succesfully!");
    });

    // Add optional subscriptions
    ASSERT_TRUE(loop->AddCallback(semaA, semACallback));
    ASSERT_TRUE(loop->AddCallback(semaB, semBCallback));
    ASSERT_TRUE(loop->AddCallbackEx(semac, semCCallback));


    // Commit source changes
    ASSERT_TRUE(loop->Commit());

    // Dispatch any (IE: semaphore A) non-blocking
    ASSERT_TRUE(loop->IsSignaled());

    // Reuse semaphore A
    semaA->AddOne(); // *1

    // And demonstrate blocking function
    ASSERT_TRUE(loop->WaitAny(0)); // *1

    // ...or what about now? now will you block?
    ASSERT_FALSE(loop->WaitAny(1000));

    // Trigger A and B
    semaB->AddOne();
    semaA->AddOne();
    
    // Dispatch all
    ASSERT_TRUE(loop->WaitAny(1000));

    // Stall for 10s unless A comes alives (it wont)
    loop->WaitAll(10000); 
    ASSERT_FALSE(loop->WaitAll(100));

    // Manually evict semaphore A
    loop->SourceRemove(semaA);
    loop->Commit();

    ASSERT_TRUE(loop->WaitAll(100));
}


TEST(Loop, Performance)
{
    SysBenchmark("Loop Performance A");

    auto semaA = Aurora::Loop::NewLSSemaphore(1);
    auto semaB = Aurora::Loop::NewLSSemaphore(0);
    auto semac = Aurora::Loop::NewLSSemaphore(0);
    auto loop = Aurora::Loop::NewLoopQueue();
    

    auto semACallback = AuMakeShared<Aurora::Loop::ILoopSourceSubscriberFunctional>([](const AuSPtr<Aurora::Loop::ILoopSource> &source) -> bool
    {
        //AuLogInfo("Hello from semaphore a's work queue");
        return false; // dont evict, we'll reuse this  *1
    });

    auto semBCallback = AuMakeShared<Aurora::Loop::ILoopSourceSubscriberFunctional>([](const AuSPtr<Aurora::Loop::ILoopSource> &source) -> bool
    {
        //AuLogInfo("Hello from semaphore b's work queue");
        return true; // evict
    });


    auto semCCallback = AuMakeShared<Aurora::Loop::ILoopSourceSubscriberExFunctional>([](const AuSPtr<Aurora::Loop::ILoopSource> &source) -> bool
    {
        //AuLogInfo("This should not have been triggered from C");
        return false;
    },

                                                                                        [](const AuSPtr<Aurora::Loop::ILoopSource> &source) -> void
    {
        //AuLogInfo("C timedout succesfully!");
    });


    /*
    ------------------------------------------------------------------------------------
    NT:

    At 10k iterations:
        [2022-03-31 13:10:29] [Debug]  | [Benchmark] Loop Performance A took 51.01004ms
        [2022-03-31 13:10:54] [Debug]  | [Benchmark] Loop Performance A took 50.02065ms

    ...not bad, here's why:
        Reece, [30/03/2022 19:39]
        1 whole frame (~20Hz) of work to blast WaitForMultipleObjectsEx/io_submit/epoll abstraction with a test covering multiple apis 10k times/iterations
        
        Reece, [30/03/2022 19:39]
        imagine a scheduling thread working on 10k unique kernel work objects per frame
        
        Reece, [30/03/2022 19:39]
        that alone isn't comparable to sockets because sockets are grouped into 1 worker event per thread
        
        Reece, [30/03/2022 19:40]
        general purpose work should go through semaphores and condition variables, not a unique object per work item
        
        Reece, [30/03/2022 19:40]
        it would be like sleeping on a kernel object 40,000 times per frame
        
        Reece, [30/03/2022 19:40]
        by "like" i mean 10k iterations * 4 apis that can dispatch a callback or yield to kernel
        
        Reece, [30/03/2022 19:42]
        best practices say you dont fucking spam resources. 40k is a hell of a lot more than, idk, checking a file read transaction a few tens-to-hundreds of times a second on an serializer thread that's not io-bound


    Further data:
        VS Profiler reports: 1.6% other, 77.5% IO, kernel: 20%
        [TODO: link]

        ...almost all of the overhead is the semaphore callbacks themselves
        [TODO: link]

    Needless to say, I think this is alright.

    ------------------------------------------------------------------------------------
    Linux: TODO: io_submit 


    ------------------------------------------------------------------------------------
    BSD: kevent is a long way away

    ------------------------------------------------------------------------------------
    */

    for (int i = 0; i < 10'000; i++)
    {
        // Add initial loop sources
        ASSERT_TRUE(loop->SourceAdd(semaA));
        ASSERT_TRUE(loop->SourceAdd(semaB));
        ASSERT_TRUE(loop->SourceAddWithTimeout(semac, 2000));

        // Add optional subscriptions
        ASSERT_TRUE(loop->AddCallback(semaA, semACallback));
        ASSERT_TRUE(loop->AddCallback(semaB, semBCallback));
        ASSERT_TRUE(loop->AddCallbackEx(semac, semCCallback));


        // Commit source changes
        ASSERT_TRUE(loop->Commit());

        // Dispatch any (IE: semaphore A) non-blocking
        ASSERT_TRUE(loop->IsSignaled());

        // Reuse semaphore A
        semaA->AddOne(); // *1

        // And demonstrate blocking function
        ASSERT_TRUE(loop->WaitAny(0)); // *1

        //ASSERT_FALSE(loop->WaitAny(1000));

        // Trigger A and B
        semaB->AddOne();
        semaA->AddOne();

        // Dispatch all
        ASSERT_TRUE(loop->WaitAny(1000));

        // Stall for 10s unless A comes alives (it wont)
        //loop->WaitAll(10000);
        //ASSERT_FALSE(loop->WaitAll(100));

        // Manually evict semaphore A
        loop->SourceRemove(semaA);
        loop->SourceRemove(semac);
        loop->Commit();

        ASSERT_TRUE(loop->WaitAll(100));

        semaA->AddOne(); // account for initial starting count of 1
    }
}

void RunTests()
{
    Aurora::RuntimeStartInfo info;
    info.console.fio.enableLogging = false;
    info.console.asyncVSLog = true;
    Aurora::RuntimeStart(info);
}