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core/vm: reduced big int allocations

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Reduced big int allocation by making stack items modifiable. Instead of
adding items such as `common.Big0` to the stack, `new(big.Int)` is
added instead. One must expect that any item that is added to the stack
might change.
This commit is contained in:
Jeffrey Wilcke
2015-08-06 23:06:47 +02:00
parent 184e9ae9a8
commit ac697326a6
4 changed files with 78 additions and 123 deletions
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17
core/vm/jit.go
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@ -404,9 +404,10 @@ func jitCalculateGasAndSize(env Environment, context *Context, caller ContextRef
mSize, mStart := stack.data[stack.len()-2], stack.data[stack.len()-1]
add := new(big.Int)
gas.Add(gas, params.LogGas)
gas.Add(gas, new(big.Int).Mul(big.NewInt(int64(n)), params.LogTopicGas))
gas.Add(gas, new(big.Int).Mul(mSize, params.LogDataGas))
gas.Add(gas, add.Mul(big.NewInt(int64(n)), params.LogTopicGas))
gas.Add(gas, add.Mul(mSize, params.LogDataGas))
newMemSize = calcMemSize(mStart, mSize)
case EXP:
@ -496,18 +497,20 @@ func jitCalculateGasAndSize(env Environment, context *Context, caller ContextRef
newMemSize.Mul(newMemSizeWords, u256(32))
if newMemSize.Cmp(u256(int64(mem.Len()))) > 0 {
// be careful reusing variables here when changing.
// The order has been optimised to reduce allocation
oldSize := toWordSize(big.NewInt(int64(mem.Len())))
pow := new(big.Int).Exp(oldSize, common.Big2, Zero)
linCoef := new(big.Int).Mul(oldSize, params.MemoryGas)
linCoef := oldSize.Mul(oldSize, params.MemoryGas)
quadCoef := new(big.Int).Div(pow, params.QuadCoeffDiv)
oldTotalFee := new(big.Int).Add(linCoef, quadCoef)
pow.Exp(newMemSizeWords, common.Big2, Zero)
linCoef = new(big.Int).Mul(newMemSizeWords, params.MemoryGas)
quadCoef = new(big.Int).Div(pow, params.QuadCoeffDiv)
newTotalFee := new(big.Int).Add(linCoef, quadCoef)
linCoef = linCoef.Mul(newMemSizeWords, params.MemoryGas)
quadCoef = quadCoef.Div(pow, params.QuadCoeffDiv)
newTotalFee := linCoef.Add(linCoef, quadCoef)
fee := new(big.Int).Sub(newTotalFee, oldTotalFee)
fee := newTotalFee.Sub(newTotalFee, oldTotalFee)
gas.Add(gas, fee)
}
}