Swift3 使用getter时，UnsafemeutableBufferPointer速度慢

我有一台装有定制光环的AVAudioEngine。当我运行引擎时，cpu会出现峰值，这似乎与UnsafemtableBufferPointer.getter和.setter操作有关：

func performRender(ioActionFlags: UnsafeMutablePointer<AudioUnitRenderActionFlags>, inTimeStamp: UnsafePointer<AudioTimeStamp>, inBusNumber: UInt32, inNumberFrames: UInt32, ioData: UnsafeMutablePointer<AudioBufferList>?) -> OSStatus {

    let blI = UnsafeMutableAudioBufferListPointer(ioData)

    let numSamples = Int((blI?[0].mDataByteSize)! / UInt32(MemoryLayout<Float32>.stride))

    for input in 0 ..< blI!.count{

        let bI = blI?[input]

        guard let inputData = bI?.mData else {

            //assert(false)

            return kAudioUnitErr_Uninitialized
        }

        let samplesBI = UnsafeMutablePointer<Float32>(inputData.assumingMemoryBound(to: Float32.self))

        let samplesI = UnsafeMutableBufferPointer<Float32>(start: samplesBI, count: numSamples)

        for sampleIndex in 0 ..< samplesI.count {

            samplesI[sampleIndex] *= 0.5
        }

    }

    return noErr
}

func performRender（ioActionFlags:UnsafeMutablePointer

什么会导致获取和设置指针数据的这种低效行为？因为它正在处理音频样本，因此低效会导致音频信号中断。
您可以跳过UnsafeMutableBufferPointer（）调用，直接为样本指针编制索引：

let bufferListPtr = UnsafeMutableAudioBufferListPointer(ioData)
...
let mBuffer : AudioBuffer = bufferListPtr[0]
let count = Int(mBuffer.mDataByteSize) / yourSampleSizeInBytes
let dataPointer = UnsafeMutableRawPointer(mBuffer.mData)
if let dptr = dataPointer {
    let sampleArray = dptr.assumingMemoryBound(to: yourSampleType.self)
    for i in 0..<(count) {
        let x = sampleArray[i]
        let y = myModifySample( x )   
        sampleArray[i] =  y 
    }
}

let bufferListPtr=UnsafeMutableAudioBufferListPointer（ioData）
...
让mBuffer:AudioBuffer=bufferListPtr[0]
让count=Int（mBuffer.mDataByteSize）/yourSampleSizeInBytes
让dataPointer=unsafemeutablerawpointer（mBuffer.mData）
如果让dptr=dataPointer{
让sampleArray=dptr.AssumingMemoryBind（到：yourSampleType.self）
因为我在0。。