/*
    Copyright (c) 2005-2020 Intel Corporation

    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

        http://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.
*/

#include "tbb/pipeline.h"
#include "tbb/spin_mutex.h"
#include "tbb/atomic.h"
#include "tbb/tbb_thread.h"
#include <cstdlib>
#include <cstdio>
#include "harness.h"

// In the test, variables related to token counting are declared
// as unsigned long to match definition of tbb::internal::Token.

//! Id of thread that first executes work on non-thread-bound stages
tbb::tbb_thread::id thread_id;
//! Zero thread id
tbb::tbb_thread::id id0;
//! True if non-thread-bound stages must be executed on one thread
bool is_serial_execution;
double sleeptime; // how long is a non-thread-bound stage to sleep?

struct Buffer {
    //! Indicates that the buffer is not used.
    static const unsigned long unused = ~0ul;
    unsigned long id;
    //! True if Buffer is in use.
    bool is_busy;
    unsigned long sequence_number;
    Buffer() : id(unused), is_busy(false), sequence_number(unused) {}
};

class waiting_probe {
    size_t check_counter;
public:
    waiting_probe() : check_counter(0) {}
    bool required( ) {
        ++check_counter;
        return !((check_counter+1)&size_t(0x7FFF));
    }
    void probe( ); // defined below
};

static const unsigned StreamSize = 10;
//! Maximum number of filters allowed
static const unsigned MaxFilters = 4;
static const unsigned MaxBuffer = 8;
static bool Done[MaxFilters][StreamSize];
static waiting_probe WaitTest;
static unsigned out_of_order_count;

#include "harness_concurrency_tracker.h"

template<typename T>
class BaseFilter: public T {
    bool* const my_done;
    const bool my_is_last;
    bool concurrency_observed;
    tbb::atomic<int> running_count;
public:
    tbb::atomic<tbb::internal::Token> current_token;
    BaseFilter( tbb::filter::mode type, bool done[], bool is_last ) :
        T(type),
        my_done(done),
        my_is_last(is_last),
        concurrency_observed(false),
        current_token()
    {
        running_count = 0;
    }
    ~BaseFilter() {
        if( this->is_serial() || is_serial_execution )
            ASSERT( !concurrency_observed, "Unexpected concurrency in a [serial] filter" );
        else if( sleeptime > 0 )
            ASSERT( concurrency_observed, "No concurrency in a parallel filter" );
    }
    virtual Buffer* get_buffer( void* item ) {
        current_token++;
        return static_cast<Buffer*>(item);
    }
    void* operator()( void* item ) __TBB_override {
        // Check if work is done only on one thread when ntokens==1 or
        // when pipeline has only one filter that is serial and non-thread-bound
        if( is_serial_execution && !this->is_bound() ) {
            // Get id of current thread
            tbb::tbb_thread::id id = tbb::this_tbb_thread::get_id();
            // At first execution, set thread_id to current thread id.
            // Serialized execution is expected, so there should be no race.
            if( thread_id == id0 )
                thread_id = id;
            // Check if work is done on one thread
            ASSERT( thread_id == id, "non-thread-bound stages executed on different threads when must be executed on a single one");
        }
        Harness::ConcurrencyTracker ct;
        concurrency_observed = concurrency_observed || (running_count++ > 0);
        if( this->is_serial() )
            ASSERT( !concurrency_observed, "premature entry to serial stage" );
 
        Buffer* b = get_buffer(item);
        if( b ) {
            if(!this->is_bound() && sleeptime > 0) {
                if(this->is_serial()) {
                    Harness::Sleep((int)sleeptime);
                } else {
                    // early parallel tokens sleep longer
                    int i = (int)((5 - (int)b->sequence_number) * sleeptime);
                    if(i < (int)sleeptime) i = (int)sleeptime;
                    Harness::Sleep(i);
                }
            }
            if( this->is_ordered() ) {
                if( b->sequence_number == Buffer::unused )
                    b->sequence_number = current_token-1;
                else
                    ASSERT( b->sequence_number==current_token-1, "item arrived out of order" );
            } else if( this->is_serial() ) {
                if( b->sequence_number != current_token-1 && b->sequence_number != Buffer::unused )
                    out_of_order_count++;
            }
            ASSERT( b->id < StreamSize, NULL );
            ASSERT( !my_done[b->id], "duplicate processing of token?" );
            ASSERT( b->is_busy, NULL );
            my_done[b->id] = true;
            if( my_is_last ) {
                b->id = Buffer::unused;
                b->sequence_number = Buffer::unused;
                __TBB_store_with_release(b->is_busy, false);
            }
        }
        concurrency_observed = concurrency_observed || (--running_count > 0);
        return b;
    }
};

template<typename T>
class InputFilter: public BaseFilter<T> {
    tbb::spin_mutex input_lock;
    Buffer buffer[MaxBuffer];
    const tbb::internal::Token my_number_of_tokens;
public:
    InputFilter( tbb::filter::mode type, tbb::internal::Token ntokens, bool done[], bool is_last ) :
        BaseFilter<T>(type, done, is_last),
        my_number_of_tokens(ntokens)
    {}
    Buffer* get_buffer( void* ) __TBB_override {
        unsigned long next_input;
        unsigned free_buffer = 0;
        { // lock protected scope
            tbb::spin_mutex::scoped_lock lock(input_lock);
            if( this->current_token>=StreamSize )
                return NULL;
            next_input = this->current_token++;
            // once in a while, emulate waiting for input; this only makes sense for serial input
            if( this->is_serial() && WaitTest.required() )
                WaitTest.probe( );
            while( free_buffer<MaxBuffer )
                if( __TBB_load_with_acquire(buffer[free_buffer].is_busy) )
                    ++free_buffer;
                else {
                    buffer[free_buffer].is_busy = true;
                    break;
                }
        }
        ASSERT( free_buffer<my_number_of_tokens, "premature reuse of buffer" );
        Buffer* b = &buffer[free_buffer];
        ASSERT( &buffer[0] <= b, NULL );
        ASSERT( b <= &buffer[MaxBuffer-1], NULL );
        ASSERT( b->id == Buffer::unused, NULL);
        b->id = next_input;
        ASSERT( b->sequence_number == Buffer::unused, NULL);
        return b;
    }
};

class process_loop {
public:
    void operator()( tbb::thread_bound_filter* tbf ) {
        tbb::thread_bound_filter::result_type flag;
        do
            flag = tbf->process_item();
        while( flag != tbb::thread_bound_filter::end_of_stream );
    }
};

//! The struct below repeats layout of tbb::pipeline.
struct hacked_pipeline {
    tbb::filter* filter_list;
    tbb::filter* filter_end;
    tbb::empty_task* end_counter;
    tbb::atomic<tbb::internal::Token> input_tokens;
    tbb::atomic<tbb::internal::Token> global_token_counter;
    bool end_of_input;
    bool has_thread_bound_filters;

    virtual ~hacked_pipeline();
};

//! The struct below repeats layout of tbb::internal::ordered_buffer.
struct hacked_ordered_buffer {
    void* array; // This should be changed to task_info* if ever used
    tbb::internal::Token array_size;
    tbb::internal::Token low_token;
    tbb::spin_mutex array_mutex;
    tbb::internal::Token high_token;
    bool is_ordered;
    bool is_bound;
};

//! The struct below repeats layout of tbb::filter.
struct hacked_filter {
    tbb::filter* next_filter_in_pipeline;
    hacked_ordered_buffer* input_buffer;
    unsigned char my_filter_mode;
    tbb::filter* prev_filter_in_pipeline;
    tbb::pipeline* my_pipeline;
    tbb::filter* next_segment;

    virtual ~hacked_filter();
};

#if _MSC_VER && !defined(__INTEL_COMPILER)
    // Workaround for overzealous compiler warnings
    // Suppress compiler warning about constant conditional expression
    #pragma warning (disable: 4127)
#endif

void clear_global_state() {
    Harness::ConcurrencyTracker::Reset();
    memset( Done, 0, sizeof(Done) );
    thread_id = id0;
    is_serial_execution = false;
}


class PipelineTest {
    // There are 3 non-thread-bound filter types: serial_in_order and serial_out_of_order, parallel
    static const tbb::filter::mode non_tb_filters_table[3]; // = { tbb::filter::serial_in_order, tbb::filter::serial_out_of_order, tbb::filter::parallel};
    // There are 2 thread-bound filter types: serial_in_order and serial_out_of_order
    static const tbb::filter::mode tb_filters_table[2]; // = { tbb::filter::serial_in_order, tbb::filter::serial_out_of_order };

    static const unsigned number_of_non_tb_filter_types = sizeof(non_tb_filters_table)/sizeof(non_tb_filters_table[0]);
    static const unsigned number_of_tb_filter_types = sizeof(tb_filters_table)/sizeof(tb_filters_table[0]);
    static const unsigned number_of_filter_types = number_of_non_tb_filter_types + number_of_tb_filter_types;
    // static unsigned my_nthread;
    public:
    static double TestOneConfiguration( unsigned numeral, unsigned nthread, unsigned number_of_filters, tbb::internal::Token ntokens);
    static void TestTrivialPipeline( unsigned nthread, unsigned number_of_filters );
    static void TestIdleSpinning(unsigned nthread);

    static void PrintConfiguration(unsigned numeral, unsigned nFilters) {
        REMARK( "{ ");
        for( unsigned i = 0; i < nFilters; ++i) {
            switch( numeral % number_of_filter_types ) {
                case 0: REMARK("s  "); break;
                case 1: REMARK("B  "); break;
                case 2: REMARK("o  "); break;
                case 3: REMARK("Bo "); break;
                case 4: REMARK("P  "); break;
                default: REMARK(" ** ERROR** "); break;
            }
            numeral /= number_of_filter_types;
        }
        REMARK("}");
    }
    static bool ContainsBoundFilter(unsigned numeral) {
        for( ;numeral != 0; numeral /= number_of_filter_types)
            if(numeral & 0x1) return true;
        return false;
    }
};

const tbb::filter::mode PipelineTest::non_tb_filters_table[3] = {
    tbb::filter::serial_in_order,       // 0
    tbb::filter::serial_out_of_order,   // 2
    tbb::filter::parallel               // 4
};
const tbb::filter::mode PipelineTest::tb_filters_table[2] = {
    tbb::filter::serial_in_order,       // 1
    tbb::filter::serial_out_of_order    // 3
};

#include "harness_cpu.h"

double PipelineTest::TestOneConfiguration(unsigned numeral, unsigned nthread, unsigned number_of_filters, tbb::internal::Token ntokens)
{
    // Build pipeline
    tbb::pipeline pipeline;
    tbb::filter* filter[MaxFilters];
    unsigned temp = numeral;
    // parallelism_limit is the upper bound on the possible parallelism
    unsigned parallelism_limit = 0;
    // number of thread-bound-filters in the current sequence
    unsigned number_of_tb_filters = 0;
    // ordinal numbers of thread-bound-filters in the current sequence
    unsigned array_of_tb_filter_numbers[MaxFilters];
    if(!ContainsBoundFilter(numeral)) return 0.0;
    for( unsigned i=0; i<number_of_filters; ++i, temp/=number_of_filter_types ) {
        bool is_bound = temp%number_of_filter_types&0x1;
        tbb::filter::mode filter_type;
        if( is_bound ) {
            filter_type = tb_filters_table[temp%number_of_filter_types/number_of_non_tb_filter_types];
        } else
            filter_type = non_tb_filters_table[temp%number_of_filter_types/number_of_tb_filter_types];
        const bool is_last = i==number_of_filters-1;
        if( is_bound ) {
            if( i == 0 )
                filter[i] = new InputFilter<tbb::thread_bound_filter>(filter_type,ntokens,Done[i],is_last);
            else
                filter[i] = new BaseFilter<tbb::thread_bound_filter>(filter_type,Done[i],is_last);
            array_of_tb_filter_numbers[number_of_tb_filters] = i;
            number_of_tb_filters++;
        } else {
            if( i == 0 )
                filter[i] = new InputFilter<tbb::filter>(filter_type,ntokens,Done[i],is_last);
            else
                filter[i] = new BaseFilter<tbb::filter>(filter_type,Done[i],is_last);
        }
        pipeline.add_filter(*filter[i]);
        if ( filter[i]->is_serial() ) {
            parallelism_limit += 1;
        } else {
            parallelism_limit = nthread;
        }
    }
    ASSERT(number_of_tb_filters,NULL);
    clear_global_state();
    // Account for clipping of parallelism.
    if( parallelism_limit>nthread )
        parallelism_limit = nthread;
    if( parallelism_limit>ntokens )
        parallelism_limit = (unsigned)ntokens;

    for( unsigned i=0; i<number_of_filters; ++i ) {
        static_cast<BaseFilter<tbb::filter>*>(filter[i])->current_token=0;
    }
    tbb::tbb_thread* t[MaxFilters];
    for( unsigned j = 0; j<number_of_tb_filters; j++)
        t[j] = new tbb::tbb_thread(process_loop(), static_cast<tbb::thread_bound_filter*>(filter[array_of_tb_filter_numbers[j]]));
    if( ntokens == 1 || ( number_of_filters == 1 && number_of_tb_filters == 0 && filter[0]->is_serial() ))
        is_serial_execution = true;
    double strttime = GetCPUUserTime();
    pipeline.run( ntokens );
    double endtime = GetCPUUserTime();
    for( unsigned j = 0; j<number_of_tb_filters; j++)
        t[j]->join();
    ASSERT( !Harness::ConcurrencyTracker::InstantParallelism(), "filter still running?" );
    for( unsigned i=0; i<number_of_filters; ++i )
        ASSERT( static_cast<BaseFilter<tbb::filter>*>(filter[i])->current_token==StreamSize, NULL );
    for( unsigned i=0; i<MaxFilters; ++i )
        for( unsigned j=0; j<StreamSize; ++j ) {
            ASSERT( Done[i][j]==(i<number_of_filters), NULL );
        }
    if( Harness::ConcurrencyTracker::PeakParallelism() < parallelism_limit )
        REMARK( "nthread=%lu ntokens=%lu MaxParallelism=%lu parallelism_limit=%lu\n",
            nthread, ntokens, Harness::ConcurrencyTracker::PeakParallelism(), parallelism_limit );
    for( unsigned i=0; i < number_of_filters; ++i ) {
        delete filter[i];
        filter[i] = NULL;
    }
    for( unsigned j = 0; j<number_of_tb_filters; j++)
        delete t[j];
    pipeline.clear();
    return endtime - strttime;
} // TestOneConfiguration

void PipelineTest::TestTrivialPipeline( unsigned nthread, unsigned number_of_filters ) {

    REMARK( "testing with %lu threads and %lu filters\n", nthread, number_of_filters );
    ASSERT( number_of_filters<=MaxFilters, "too many filters" );
    tbb::internal::Token max_tokens = nthread < MaxBuffer ? nthread : MaxBuffer;
    // The loop has 1 iteration if max_tokens=1 and 2 iterations if max_tokens>1:
    // one iteration for ntokens=1 and second for ntokens=max_tokens
    // Iteration for ntokens=1 is required in each test case to check if pipeline run only on one thread
    unsigned max_iteration = max_tokens > 1 ? 2 : 1;
    tbb::internal::Token ntokens = 1;
    for( unsigned iteration = 0; iteration < max_iteration; iteration++) {
        if( iteration > 0 )
            ntokens = max_tokens;
        // Count maximum iterations number
        unsigned limit = 1;
        for( unsigned i=0; i<number_of_filters; ++i)
            limit *= number_of_filter_types;
        // Iterate over possible filter sequences
        for( unsigned numeral=0; numeral<limit; ++numeral ) {
            REMARK( "testing configuration %lu of %lu\n", numeral, limit );
            (void)TestOneConfiguration(numeral, nthread, number_of_filters, ntokens);
        }
    }
}

// varying times for sleep result in different user times for all pipelines.
// So we compare the running time of an all non-TBF pipeline with different (with
// luck representative) TBF configurations.
//
// We run the tests multiple times and compare the average runtimes for those cases
// that don't return 0 user time.  configurations that exceed the allowable extra
// time are reported.
void PipelineTest::TestIdleSpinning( unsigned nthread)  {
    unsigned sample_setups[] = {
        // in the comments below, s == serial, o == serial out-of-order,
        // B == thread bound, Bo == thread bound out-of-order, p == parallel
        1,   // B  s  s  s
        5,   // s  B  s  s
        25,  // s  s  B  s
        125, // s  s  s  B
        6,   // B  B  s  s
        26,  // B  s  B  s
        126, // B  s  s  B
        30,  // s  B  B  s
        130, // s  B  s  B
        150, // s  s  B  B
        31,  // B  B  B  s
        131, // B  B  s  B
        155, // s  B  B  B
        495, // s  p  p  Bo
        71,  // B  p  o  s
        355, // s  B  p  o
        95,  // s  p  Bo s
        475, // s  s  p  Bo
    };
    const int nsetups = sizeof(sample_setups) / sizeof(unsigned);
    const int ntests = 4;
    const double bignum = 1000000000.0;
    const double allowable_slowdown = 3.5;
    unsigned zero_count = 0;

    REMARK( "testing idle spinning with %lu threads\n", nthread );
    tbb::internal::Token max_tokens = nthread < MaxBuffer ? nthread : MaxBuffer;
    for( int i=0; i<nsetups; ++i ) {
        unsigned numeral = sample_setups[i];
        unsigned temp = numeral;
        unsigned nbound = 0;
        while(temp) {
            if((temp%number_of_filter_types)&0x01) nbound++;
            temp /= number_of_filter_types;
        }
        sleeptime = 20.0;
        double s0 = bignum;
        double s1 = bignum;
        int v0cnt = 0;
        int v1cnt = 0;
        double s0sum = 0.0;
        double s1sum = 0.0;
        REMARK(" TestOneConfiguration, pipeline == ");
        PrintConfiguration(numeral, MaxFilters);
        REMARK(", max_tokens== %d\n", (int)max_tokens);
        for(int j = 0; j < ntests; ++j) {
            double s1a = TestOneConfiguration(numeral, nthread, MaxFilters, max_tokens);
            double s0a = TestOneConfiguration((unsigned)0, nthread, MaxFilters, max_tokens);
            s1sum += s1a;
            s0sum += s0a;
            if(s0a > 0.0) {
                ++v0cnt;
                s0 = (s0a < s0) ? s0a : s0;
            } else {
                ++zero_count;
            }
            if(s1a > 0.0) {
                ++v1cnt;
                s1 = (s1a < s1) ? s1a : s1;
            } else {
                ++zero_count;
            }
        }
        if(s0 == bignum || s1 == bignum) continue;
        s0sum /= (double)v0cnt;
        s1sum /= (double)v1cnt;
        double slowdown = (s1sum-s0sum)/s0sum;
        if(slowdown > allowable_slowdown)
            REMARK( "with %lu threads configuration %lu has slowdown > %g (%g)\n", nthread, numeral, allowable_slowdown, slowdown );
    }
    REMARK("Total of %lu zero times\n", zero_count);
}

static int nthread; // knowing number of threads is necessary to call TestCPUUserTime

void waiting_probe::probe( ) {
    if( nthread==1 ) return;
    REMARK("emulating wait for input\n");
    // Test that threads sleep while no work.
    // The master doesn't sleep so there could be 2 active threads if a worker is waiting for input
    TestCPUUserTime(nthread, 2);
}

#include "tbb/task_scheduler_init.h"

int TestMain () {
    out_of_order_count = 0;
    if( MinThread<1 ) {
        REPORT("must have at least one thread");
        exit(1);
    }

    // Test with varying number of threads.
    for( nthread=MinThread; nthread<=MaxThread; ++nthread ) {
        // Initialize TBB task scheduler
        tbb::task_scheduler_init init(nthread);
        sleeptime = 0.0;  // msec : 0 == no_timing, > 0, each filter stage sleeps for sleeptime

        // Test pipelines with 1 and maximal number of filters
        for( unsigned n=1; n<=MaxFilters; n*=MaxFilters ) {
            // Thread-bound stages are serviced by user-created threads; those
            // don't run the pipeline and don't service non-thread-bound stages
            PipelineTest::TestTrivialPipeline(nthread,n);
        }

        // Test that all workers sleep when no work
        TestCPUUserTime(nthread);
        if((unsigned)nthread >= MaxFilters)  // test works when number of threads >= number of stages
            PipelineTest::TestIdleSpinning(nthread);
    }
    if( !out_of_order_count )
        REPORT("Warning: out of order serial filter received tokens in order\n");
    return Harness::Done;
}
