(Android) Unity got Poor CPU Performance compared with Native apk

Hello everyone, my team have been contributing to develop " view dependent media player ", which using a single thread decode 2048 * 1536 with android-media-codec (we can call it BASE TEX) and four thread decode 512 * 256 * 24 split blocks for viewer directly look at with ffmpeg (we can call it HD TEX), very similar with VR_5K_PLAYER.

The above main framework make the cpu usage more heavy compare with gpu. Cpu need decode 2048 *1536 totally and upload YUV from memory to video memory every frame, while gpu only decode 2048 *1536. After a few test with Samsung S8 & Quest, i found that, s8 & Quest got different performance which s8 got a high fps because of Quest has less cpu avaliability compare with S8.

( PS: S8 & Quest all equiped with snapdragon 835. as far as i know, the 835 chip contain 8 core,  4 core of all 8 core are big core responsible for heavy work )

To confirm my point of view , i made a test proj using unity &  the latest gear sdk, add heavy cpu work for some thread

public class NewBehaviourScript : MonoBehaviour {
  // Use this for initialization
  void Start ()
  {
    for (int i = 0; i < 8; i++)
    {
      ThreadStart method = () => threadWork();
      Thread thread = new Thread(method);
      thread.Start();
    }

   void Update()
   {
      long sum = 0;
      for (int i = 0; i < 1000000; ++i)
        sum = (int)((sum + i) * 2.0f / 2.0f);
    }

    void threadWork()
    {
      while (true)
      {
        long sum = 0;
        for (int i = 0; i < 100000000; ++i)
              sum = (int)((sum + i) * 2.0f / 2.0f);
             Debug.LogFormat("TestThread End name:{0} curr thread id:{1} cur timeStamp:{2}", sum, Thread.CurrentThread.ManagedThreadId, DateTime.Now.ToString());
      }
    }
  }

the enclosed python file use "adb shell cat /proc/stat" to calculate 8 core usage. 

 

the above result is S8, the last four core are big core usage, while 3 big core execute full load.