From 8bd421fb0b7400da95517203bf398e8a55cf71bd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A9ter=20Szil=C3=A1gyi?= <peterke@gmail.com>
Date: Wed, 28 Sep 2016 13:17:17 +0300
Subject: [PATCH] cmd, core, params: use gas-per-second block limiting

---
 cmd/geth/main.go         |  2 +-
 cmd/geth/usage.go        |  2 +-
 cmd/utils/flags.go       | 10 +++++-----
 core/blockchain.go       | 22 ++++++++++++----------
 params/miner_strategy.go |  7 +++----
 5 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/cmd/geth/main.go b/cmd/geth/main.go
index 6606fbac6c..6d6dee45e0 100644
--- a/cmd/geth/main.go
+++ b/cmd/geth/main.go
@@ -150,7 +150,7 @@ participating.
 		utils.MiningGPUFlag,
 		utils.AutoDAGFlag,
 		utils.TargetGasLimitFlag,
-		utils.BlockTimeLimitFlag,
+		utils.GasPerSecondFlag,
 		utils.NATFlag,
 		utils.NatspecEnabledFlag,
 		utils.NoDiscoverFlag,
diff --git a/cmd/geth/usage.go b/cmd/geth/usage.go
index 4bb7936669..84a30f3752 100644
--- a/cmd/geth/usage.go
+++ b/cmd/geth/usage.go
@@ -126,7 +126,7 @@ var AppHelpFlagGroups = []flagGroup{
 			utils.AutoDAGFlag,
 			utils.EtherbaseFlag,
 			utils.TargetGasLimitFlag,
-			utils.BlockTimeLimitFlag,
+			utils.GasPerSecondFlag,
 			utils.GasPriceFlag,
 			utils.ExtraDataFlag,
 		},
diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index 6ae3f26d44..a6d489e1e7 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -183,10 +183,10 @@ var (
 		Usage: "Sets the artificial target gas floor for the blocks to mine",
 		Value: params.GenesisGasLimit.String(),
 	}
-	BlockTimeLimitFlag = cli.IntFlag{
-		Name:  "blocktimelimit",
-		Usage: "Time limit for processing a block after which to halve the hard gas limit",
-		Value: 5,
+	GasPerSecondFlag = cli.StringFlag{
+		Name:  "gaspersec",
+		Usage: "Gas consumption per second below which to tighten the block limits",
+		Value: params.GasPerSecondThreshold.String(),
 	}
 	AutoDAGFlag = cli.BoolFlag{
 		Name:  "autodag",
@@ -752,7 +752,7 @@ func SetupNetwork(ctx *cli.Context) {
 	}
 	params.TargetGasLimit = common.String2Big(ctx.GlobalString(TargetGasLimitFlag.Name))
 	params.CurrentGasCeil.Set(params.TargetGasLimit)
-	params.BlockTimeLimit = time.Duration(ctx.GlobalInt(BlockTimeLimitFlag.Name)) * time.Second
+	params.GasPerSecondThreshold = common.String2Big(ctx.GlobalString(GasPerSecondFlag.Name))
 }
 
 // MustMakeChainConfig reads the chain configuration from the database in ctx.Datadir.
diff --git a/core/blockchain.go b/core/blockchain.go
index 179ccc1925..9500d93747 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -980,17 +980,19 @@ func (self *BlockChain) InsertChain(chain types.Blocks) (int, error) {
 		stats.processed++
 
 		// Update the current gas limit (mining only) based on import times
-		params.CurrentGasCeilLock.Lock()
-		if time.Since(bstart) > params.BlockTimeLimit {
-			ceil := new(big.Int).Div(params.CurrentGasCeil, params.CurrentGasCeilCutDiv)
-			params.CurrentGasCeil.Set(common.BigMax(ceil, params.MinGasLimit))
-		} else {
-			ceil := new(big.Int).Add(params.CurrentGasCeil, new(big.Int).Div(params.CurrentGasCeil, params.CurrentGasCeilIncDiv))
-			limit := new(big.Int).Mul(chain[i].GasLimit(), big.NewInt(2))
-			params.CurrentGasCeil.Set(common.BigMin(ceil, limit))
+		if gasUsed := chain[i].GasUsed(); gasUsed.Cmp(common.Big0) > 0 {
+			params.CurrentGasCeilLock.Lock()
+			if gasPerSecond := gasUsed.Uint64() * uint64(time.Second) / uint64(time.Since(bstart)); gasPerSecond < params.GasPerSecondThreshold.Uint64() {
+				ceil := new(big.Int).Div(params.CurrentGasCeil, params.CurrentGasCeilCutDiv)
+				params.CurrentGasCeil.Set(common.BigMax(ceil, params.MinGasLimit))
+			} else {
+				ceil := new(big.Int).Add(params.CurrentGasCeil, new(big.Int).Div(params.CurrentGasCeil, params.CurrentGasCeilIncDiv))
+				limit := new(big.Int).Mul(chain[i].GasLimit(), big.NewInt(2))
+				params.CurrentGasCeil.Set(common.BigMin(ceil, limit))
+			}
+			glog.V(logger.Debug).Infof("block gas ceiling changed to %v", params.CurrentGasCeil)
+			params.CurrentGasCeilLock.Unlock()
 		}
-		glog.V(logger.Debug).Infof("block gas ceiling changed to %v", params.CurrentGasCeil)
-		params.CurrentGasCeilLock.Unlock()
 	}
 
 	if (stats.queued > 0 || stats.processed > 0 || stats.ignored > 0) && bool(glog.V(logger.Info)) {
diff --git a/params/miner_strategy.go b/params/miner_strategy.go
index c5c1cabfc0..4ce483aad1 100644
--- a/params/miner_strategy.go
+++ b/params/miner_strategy.go
@@ -19,13 +19,12 @@ package params
 import (
 	"math/big"
 	"sync"
-	"time"
 )
 
 var (
-	GenesisGasLimit = big.NewInt(4712388)               // Gas limit of the Genesis block.
-	TargetGasLimit  = new(big.Int).Set(GenesisGasLimit) // The artificial target
-	BlockTimeLimit  = 5 * time.Second                   // Block processing time limit to reduce gas after
+	GenesisGasLimit       = big.NewInt(4712388)               // Gas limit of the Genesis block.
+	TargetGasLimit        = new(big.Int).Set(GenesisGasLimit) // The artificial target
+	GasPerSecondThreshold = big.NewInt(4712388 / 2)           // Threshold below which to start reducing block gas limits
 
 	// Temp hack to get a dynamic gas limit in palace (clean up!!!)
 	CurrentGasCeil       = new(big.Int).Set(GenesisGasLimit)