Profiling Tool for Unity that Finds Peaks in Frame Time Usage (Lags)

FrameTimeBudget.cs

using System.Collections.Generic;
using System.Linq;
using UnityEngine;

public class FrameTimeBudget : MonoBehaviour
{
    // Serialized Fields
    [SerializeField]
    [Tooltip("The target frame rate. This is used to calculate the available frame time.\n\n" +
             "30 fps = 33.333 ms per frame\n60 fps = 16.666 ms per frame\n90 fps = 11.111 ms per frame")]
    private float _fpsGoal = 30f;
    [SerializeField]
    [Tooltip("The interval in seconds at which to log frame time data. Set to 0 to disable.")]
    private float _logIntervalSeconds = 5f;
    [SerializeField]
    [Tooltip("Activate this to issue a warning each time a frame exceeds the maximum.")]
    private bool _warnIfFrameTimeExceeded = true;

    // Private Fields
    private float[] _frameTimes;
    private bool _listLocked = false;
    private int _index;

    // Properties
    public int FrameTimeDataSize => (int)(100f * _logIntervalSeconds);
    private float MaxFrameTimeMilliseconds => 1000 / _fpsGoal;
    public float AverageFrameTime
    {
        get
        {
            if (_frameTimes.Length == 0) return 0;

            // Lock the list to prevent it from being modified while we're reading it
            _listLocked = true;

            // Count all values that have been filled and are not -1
            int count = 0;
            float averageFrameTime = 0;
            for (int i = 0; i < _frameTimes.Length; i++)
            {
                if (_frameTimes[i] == -1) break;
                averageFrameTime += _frameTimes[i];
                count++;
            }

            _listLocked = false;

            return averageFrameTime / count;
        }
    }
    public float MaximumFrameTime => _frameTimes.Max();
    public float MinimumFrameTime => _frameTimes.Where(time => time >= 0).Min();


#if UNITY_EDITOR || DEVELOPMENT_BUILD
    private void Start()
    {
        // Initialize the array and fill it with -1
        _frameTimes = new float[FrameTimeDataSize];
        ClearFrameTimeData();

        // Start logging frame time data
        if (_logIntervalSeconds > 0)
        {
            InvokeRepeating(nameof(LogFrameTimeData), _logIntervalSeconds, _logIntervalSeconds);
        }
    }

    private void Update()
    {
        if (_logIntervalSeconds == 0 && !_warnIfFrameTimeExceeded) return;

        float currentFrameTime = Time.deltaTime;
        if (_warnIfFrameTimeExceeded)
        {
            if (currentFrameTime > MaxFrameTimeMilliseconds / 1000)
            {
                Debug.LogFormat(LogType.Warning, LogOption.NoStacktrace, null,
                    $"Frame time exceeded the maximum of {MaxFrameTimeMilliseconds,0:N3}. Frame ms: {currentFrameTime * 1000,0:N3} ms");
            }
        }

        if (_listLocked) return;

        // Add new value, overwriting the oldest value
        _frameTimes[_index] = currentFrameTime;

        // Increment the index (wrapping back to 0)
        _index = (_index + 1) % FrameTimeDataSize;
    }

    private void LogFrameTimeData()
    {
        // Log average, max, and min frame times
        Debug.LogFormat(LogType.Log, LogOption.NoStacktrace, null,
            $"Frame time data (should not exceed {MaxFrameTimeMilliseconds,0:N2} ms). Average: {AverageFrameTime * 1000,0:N2} ms, " +
            $"Peak: {MaximumFrameTime * 1000,0:N2} ms, " +
            $"Minimum: {MinimumFrameTime * 1000,0:N2} ms");

        ClearFrameTimeData();
    }

    private void ClearFrameTimeData()
    {
        if (_listLocked) return;
        _listLocked = true;

        for (int i = 0; i < _frameTimes.Length; i++)
        {
            _frameTimes[i] = -1;
        }
        _index = 0;

        _listLocked = false;
    }
#endif
}