EOS 增發與生產者的獎勵制度

　　EOS每年增發1%的機制在系統合約中，其實說每年增發1%只是一年的總數，其實是只要在出塊，EOS就在增發的路途中，下面分析一下增發的代碼。

　　其實增發的1%的都是分給所有區塊生產者的，只要出塊了或者獲得投票都有獎勵，代碼在producer_pay.cpp文件中，只有下面兩個函數。

 

 void system_contract::onblock( block_timestamp timestamp, account_name producer ) {
      using namespace eosio;

      require_auth(N(eosio));

      /** until activated stake crosses this threshold no new rewards are paid */
      if( _gstate.total_activated_stake < min_activated_stake )
         return;

      if( _gstate.last_pervote_bucket_fill == 0 )  /// start the presses
         _gstate.last_pervote_bucket_fill = current_time();


      /**
       * At startup the initial producer may not be one that is registered / elected
       * and therefore there may be no producer object for them.
       */
      auto prod = _producers.find(producer);
      if ( prod != _producers.end() ) {
         _gstate.total_unpaid_blocks++;
         _producers.modify( prod, 0, [&](auto& p ) {
               p.unpaid_blocks++;
         });
      }

      /// only update block producers once every minute, block_timestamp is in half seconds
      if( timestamp.slot - _gstate.last_producer_schedule_update.slot > 120 ) {
         update_elected_producers( timestamp );

         if( (timestamp.slot - _gstate.last_name_close.slot) > blocks_per_day ) {
            name_bid_table bids(_self,_self);
            auto idx = bids.get_index<N(highbid)>();
            auto highest = idx.begin();
            if( highest != idx.end() &&
                highest->high_bid > 0 &&
                highest->last_bid_time < (current_time() - useconds_per_day) &&
                _gstate.thresh_activated_stake_time > 0 &&
                (current_time() - _gstate.thresh_activated_stake_time) > 14 * useconds_per_day ) {
                   _gstate.last_name_close = timestamp;
                   idx.modify( highest, 0, [&]( auto& b ){
                         b.high_bid = -b.high_bid;
               });
            }
         }
      }
   }

　　這個onlock函數在每次生產者出塊的時候都會被調用，見證者收到區塊后也會調用(相當於驗證區塊)，每次生產者出塊都會把該生產者的出塊數進行統計，把所有的區塊也進行統計，后面的代碼不太清楚在做什么，后續再補充。

　　

　　

void system_contract::claimrewards( const account_name& owner ) {
      require_auth(owner);

      const auto& prod = _producers.get( owner );
      eosio_assert( prod.active(), "producer does not have an active key" );

      eosio_assert( _gstate.total_activated_stake >= min_activated_stake,
                    "cannot claim rewards until the chain is activated (at least 15% of all tokens participate in voting)" );

      auto ct = current_time();

      eosio_assert( ct - prod.last_claim_time > useconds_per_day, "already claimed rewards within past day" );

      const asset token_supply   = token( N(eosio.token)).get_supply(symbol_type(system_token_symbol).name() );
      const auto usecs_since_last_fill = ct - _gstate.last_pervote_bucket_fill;

      if( usecs_since_last_fill > 0 && _gstate.last_pervote_bucket_fill > 0 ) {
         auto new_tokens = static_cast<int64_t>( (continuous_rate * double(token_supply.amount) * double(usecs_since_last_fill)) / double(useconds_per_year) );

         auto to_producers       = new_tokens / 5;
         auto to_savings         = new_tokens - to_producers;
         auto to_per_block_pay   = to_producers / 4;
         auto to_per_vote_pay    = to_producers - to_per_block_pay;

         INLINE_ACTION_SENDER(eosio::token, issue)( N(eosio.token), {{N(eosio),N(active)}},
                                                    {N(eosio), asset(new_tokens), std::string("issue tokens for producer pay and savings")} );

         INLINE_ACTION_SENDER(eosio::token, transfer)( N(eosio.token), {N(eosio),N(active)},
                                                       { N(eosio), N(eosio.saving), asset(to_savings), "unallocated inflation" } );

         INLINE_ACTION_SENDER(eosio::token, transfer)( N(eosio.token), {N(eosio),N(active)},
                                                       { N(eosio), N(eosio.bpay), asset(to_per_block_pay), "fund per-block bucket" } );

         INLINE_ACTION_SENDER(eosio::token, transfer)( N(eosio.token), {N(eosio),N(active)},
                                                       { N(eosio), N(eosio.vpay), asset(to_per_vote_pay), "fund per-vote bucket" } );

         _gstate.pervote_bucket  += to_per_vote_pay;
         _gstate.perblock_bucket += to_per_block_pay;

         _gstate.last_pervote_bucket_fill = ct;
      }

      int64_t producer_per_block_pay = 0;
      if( _gstate.total_unpaid_blocks > 0 ) {
         producer_per_block_pay = (_gstate.perblock_bucket * prod.unpaid_blocks) / _gstate.total_unpaid_blocks;
      }
      int64_t producer_per_vote_pay = 0;
      if( _gstate.total_producer_vote_weight > 0 ) {
         producer_per_vote_pay  = int64_t((_gstate.pervote_bucket * prod.total_votes ) / _gstate.total_producer_vote_weight);
      }
      if( producer_per_vote_pay < min_pervote_daily_pay ) {
         producer_per_vote_pay = 0;
      }
      _gstate.pervote_bucket      -= producer_per_vote_pay;
      _gstate.perblock_bucket     -= producer_per_block_pay;
      _gstate.total_unpaid_blocks -= prod.unpaid_blocks;

      _producers.modify( prod, 0, [&](auto& p) {
          p.last_claim_time = ct;
          p.unpaid_blocks = 0;
      });

      if( producer_per_block_pay > 0 ) {
         INLINE_ACTION_SENDER(eosio::token, transfer)( N(eosio.token), {N(eosio.bpay),N(active)},
                                                       { N(eosio.bpay), owner, asset(producer_per_block_pay), std::string("producer block pay") } );
      }
      if( producer_per_vote_pay > 0 ) {
         INLINE_ACTION_SENDER(eosio::token, transfer)( N(eosio.token), {N(eosio.vpay),N(active)},
                                                       { N(eosio.vpay), owner, asset(producer_per_vote_pay), std::string("producer vote pay") } );
      }
   }

} //namespace eosiosy

　　

　　先理清一下概念：

　　_gstate.pervote_bucket //所有生產者獲得投票的獎勵資金
　　_gstate.perblock_bucket //所有出塊的獎勵資金
　　_gstate.total_unpaid_blocks //公鏈上還沒有領取出塊獎勵的所有區塊數

　　這里的做法是：

　　1.每個生產者至少每隔一天可以領取獎勵；

　　2.出塊的資金數目分為兩部：把20%當做獎勵發放給生產者；把80%放在了系統用戶eosio.saving下面。

　　3.資金池為總數的20%，每個生產者領取的獎勵計算方式： 生產者出塊數 / 所有未領取獎勵的區塊數  * 25% + 生產者獲得的投票數 / 公鏈上所有的投票數  * 75%（25%和75%的比例是指獎金池的比例）

　　4.因為是增發，所有eosio用戶也會同步發行同等代幣(總數的20%，)；

　　5.出塊的獎勵資金會臨時放在系統用戶eosio.bpay下， 獲得的投票收益臨時放在eosio.vpay用戶下，但又馬上轉給了生產者，這樣的設計暫時沒有弄明白(為什么不直接轉帳給生產者)。