ExampleClass.cs

using UnityEngine;
using UnityEngine.Profiling;

public class ExampleClass : MonoBehaviour
{
    Recorder behaviourUpdateRecorder;
    void Start()
    {
        // Profilerから”BehaviourUpdate”と名前の付く項目を抽出して、
        // 観測を有効化
        behaviourUpdateRecorder = Recorder.Get("BehaviourUpdate");
        behaviourUpdateRecorder.enabled = true;
    }

    void Update()
    {
        // BehaviourUpdateが観測可能（EditorとDevelopment Players）なら、ログに処理時間（ミリ秒）を出力
        if (behaviourUpdateRecorder.isValid)
            Debug.Log("BehaviourUpdate time: " + behaviourUpdateRecorder.elapsedNanoseconds);
    }
}

https://docs.unity3d.com/ScriptReference/Profiling.Recorder.html