// Copyright (c) 2009-2011, Tor M. Aamodt, Ali Bakhoda, George L. Yuan,
// The University of British Columbia
// All rights reserved.
//
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// modification, are permitted provided that the following conditions are met:
//
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#include "dram_sched.h"
#include "gpu-misc.h"
#include "gpu-sim.h"
#include "../abstract_hardware_model.h"
#include "mem_latency_stat.h"

frfcfs_scheduler::frfcfs_scheduler( const memory_config *config, dram_t *dm, memory_stats_t *stats )
{
   m_config = config;
   m_stats = stats;
   m_num_pending = 0;
   m_num_write_pending = 0;
   m_dram = dm;
   m_queue = new std::list<dram_req_t*>[m_config->nbk];
   m_bins = new std::map<unsigned,std::list<std::list<dram_req_t*>::iterator> >[ m_config->nbk ];
   m_last_row = new std::list<std::list<dram_req_t*>::iterator>*[ m_config->nbk ];
   curr_row_service_time = new unsigned[m_config->nbk];
   row_service_timestamp = new unsigned[m_config->nbk];
   for ( unsigned i=0; i < m_config->nbk; i++ ) {
      m_queue[i].clear();
      m_bins[i].clear();
      m_last_row[i] = NULL;
      curr_row_service_time[i] = 0;
      row_service_timestamp[i] = 0;
   }
   if(m_config->seperate_write_queue_enabled) {
	   m_write_queue = new std::list<dram_req_t*>[m_config->nbk];
	   m_write_bins = new std::map<unsigned,std::list<std::list<dram_req_t*>::iterator> >[ m_config->nbk ];
	   m_last_write_row = new std::list<std::list<dram_req_t*>::iterator>*[ m_config->nbk ];

	   for ( unsigned i=0; i < m_config->nbk; i++ ) {
	         m_write_queue[i].clear();
	         m_write_bins[i].clear();
	         m_last_write_row[i] = NULL;
	      }
   }
   m_mode = READ_MODE;

}

void frfcfs_scheduler::add_req( dram_req_t *req )
{
  if(m_config->seperate_write_queue_enabled && req->data->is_write()) {
	  assert(m_num_write_pending < m_config->gpgpu_frfcfs_dram_write_queue_size);
	  m_num_write_pending++;
	  m_write_queue[req->bk].push_front(req);
	  std::list<dram_req_t*>::iterator ptr = m_write_queue[req->bk].begin();
	  m_write_bins[req->bk][req->row].push_front( ptr ); //newest reqs to the front
  } else {
	   assert(m_num_pending < m_config->gpgpu_frfcfs_dram_sched_queue_size);
	   m_num_pending++;
	   m_queue[req->bk].push_front(req);
	   std::list<dram_req_t*>::iterator ptr = m_queue[req->bk].begin();
	   m_bins[req->bk][req->row].push_front( ptr ); //newest reqs to the front
  }
}

void frfcfs_scheduler::data_collection(unsigned int bank)
{
   if (gpu_sim_cycle > row_service_timestamp[bank]) {
      curr_row_service_time[bank] = gpu_sim_cycle - row_service_timestamp[bank];
      if (curr_row_service_time[bank] > m_stats->max_servicetime2samerow[m_dram->id][bank])
         m_stats->max_servicetime2samerow[m_dram->id][bank] = curr_row_service_time[bank];
   }
   curr_row_service_time[bank] = 0;
   row_service_timestamp[bank] = gpu_sim_cycle;
   if (m_stats->concurrent_row_access[m_dram->id][bank] > m_stats->max_conc_access2samerow[m_dram->id][bank]) {
      m_stats->max_conc_access2samerow[m_dram->id][bank] = m_stats->concurrent_row_access[m_dram->id][bank];
   }
   m_stats->concurrent_row_access[m_dram->id][bank] = 0;
   m_stats->num_activates[m_dram->id][bank]++;
}

dram_req_t *frfcfs_scheduler::schedule( unsigned bank, unsigned curr_row )
{
   //row
   bool rowhit = true;
   std::list<dram_req_t*> *m_current_queue = m_queue;
   std::map<unsigned,std::list<std::list<dram_req_t*>::iterator> > *m_current_bins = m_bins ;
   std::list<std::list<dram_req_t*>::iterator> **m_current_last_row = m_last_row;

   if(m_config->seperate_write_queue_enabled) {
	   if(m_mode == READ_MODE &&
			  ((m_num_write_pending >= m_config->write_high_watermark )
			  // || (m_queue[bank].empty() && !m_write_queue[bank].empty())
			   )) {
		   m_mode = WRITE_MODE;
	   }
	   else if(m_mode == WRITE_MODE &&
				  (( m_num_write_pending < m_config->write_low_watermark )
				 //  || (!m_queue[bank].empty() && m_write_queue[bank].empty())
				   )){
		   m_mode = READ_MODE;
	   }
   }

   if(m_mode == WRITE_MODE) {
	   m_current_queue = m_write_queue;
	   m_current_bins = m_write_bins ;
	   m_current_last_row = m_last_write_row;
   }

   if ( m_current_last_row[bank] == NULL ) {
      if ( m_current_queue[bank].empty() )
         return NULL;

      std::map<unsigned,std::list<std::list<dram_req_t*>::iterator> >::iterator bin_ptr = m_current_bins[bank].find( curr_row );
      if ( bin_ptr == m_current_bins[bank].end()) {
         dram_req_t *req = m_current_queue[bank].back();
         bin_ptr = m_current_bins[bank].find( req->row );
         assert( bin_ptr != m_current_bins[bank].end() ); // where did the request go???
         m_current_last_row[bank] = &(bin_ptr->second);
         data_collection(bank);
         rowhit = false;
      } else {
    	  m_current_last_row[bank] = &(bin_ptr->second);
         rowhit = true;
      }
   }
   std::list<dram_req_t*>::iterator next = m_current_last_row[bank]->back();
   dram_req_t *req = (*next);

   //rowblp stats
    m_dram->access_num++;
    bool is_write = req->data->is_write();
    if(is_write)
  	  m_dram->write_num++;
    else
  	  m_dram->read_num++;

    if(rowhit) {
     m_dram->hits_num++;
     if(is_write)
    	  m_dram->hits_write_num++;
      else
    	  m_dram->hits_read_num++;
    }

   m_stats->concurrent_row_access[m_dram->id][bank]++;
   m_stats->row_access[m_dram->id][bank]++;
   m_current_last_row[bank]->pop_back();

   m_current_queue[bank].erase(next);
   if ( m_current_last_row[bank]->empty() ) {
	   m_current_bins[bank].erase( req->row );
	   m_current_last_row[bank] = NULL;
   }
#ifdef DEBUG_FAST_IDEAL_SCHED
   if ( req )
      printf("%08u : DRAM(%u) scheduling memory request to bank=%u, row=%u\n", 
             (unsigned)gpu_sim_cycle, m_dram->id, req->bk, req->row );
#endif

   if(m_config->seperate_write_queue_enabled && req->data->is_write()) {
	   assert( req != NULL && m_num_write_pending != 0 );
	   m_num_write_pending--;
   }
   else {
	   assert( req != NULL && m_num_pending != 0 );
	   m_num_pending--;
   }

   return req;
}


void frfcfs_scheduler::print( FILE *fp )
{
   for ( unsigned b=0; b < m_config->nbk; b++ ) {
      printf(" %u: queue length = %u\n", b, (unsigned)m_queue[b].size() );
   }
}

void dram_t::scheduler_frfcfs()
{
   unsigned mrq_latency;
   frfcfs_scheduler *sched = m_frfcfs_scheduler;
   while ( !mrqq->empty() ) {
      dram_req_t *req = mrqq->pop();

      // Power stats
      //if(req->data->get_type() != READ_REPLY && req->data->get_type() != WRITE_ACK)
      m_stats->total_n_access++;

      if(req->data->get_type() == WRITE_REQUEST){
    	  m_stats->total_n_writes++;
      }else if(req->data->get_type() == READ_REQUEST){
    	  m_stats->total_n_reads++;
      }

      req->data->set_status(IN_PARTITION_MC_INPUT_QUEUE,gpu_sim_cycle+gpu_tot_sim_cycle);
      sched->add_req(req);
   }

   dram_req_t *req;
   unsigned i;
   for ( i=0; i < m_config->nbk; i++ ) {
      unsigned b = (i+prio)%m_config->nbk;
      if ( !bk[b]->mrq ) {

         req = sched->schedule(b, bk[b]->curr_row);

         if ( req ) {
            req->data->set_status(IN_PARTITION_MC_BANK_ARB_QUEUE,gpu_sim_cycle+gpu_tot_sim_cycle);
            prio = (prio+1)%m_config->nbk;
            bk[b]->mrq = req;
            if (m_config->gpgpu_memlatency_stat) {
               mrq_latency = gpu_sim_cycle + gpu_tot_sim_cycle - bk[b]->mrq->timestamp;
               m_stats->tot_mrq_latency += mrq_latency;
               m_stats->tot_mrq_num++;
               bk[b]->mrq->timestamp = gpu_tot_sim_cycle + gpu_sim_cycle;
               m_stats->mrq_lat_table[LOGB2(mrq_latency)]++;
               if (mrq_latency > m_stats->max_mrq_latency) {
                  m_stats->max_mrq_latency = mrq_latency;
               }
            }

            break;
         }
      }
   }
}