How to use the MicroProfiler on Roblox — Transcript

Full transcript

1. 0:00hi everyone it's Andrew from roblock in
2. 0:02this video we'll dive into the micro
3. 0:04profiler what it is and why it's so
4. 0:05powerful we'll get oriented troubleshoot
5. 0:08a performance issue and even do some
6. 0:09math everyone loves math the micro
7. 0:12profiler is a performance optimization
8. 0:13and troubleshooting tool rather than
9. 0:16higher level averages like frames per
10. 0:17second the micro profiler lets you get
11. 0:19down to the well micro level you can
12. 0:22examine individual frames and all of the
13. 0:24processes that make up those frames as
14. 0:27you might imagine this level of detail
15. 0:28comes with a bit of complexity
16. 0:30I'm using Studio here for convenience
17. 0:32but the best place to use the micro
18. 0:34profiler is in the Roblox client on the
19. 0:36lowest end device that you want to
20. 0:38support to open the micro profiler press
21. 0:40control F6 on Windows or command F6 on
22. 0:43Mac OS you'll see a bunch of bars appear
23. 0:45at the top of the screen each bar
24. 0:47represents one frame from your
25. 0:49experience with new frames flowing in
26. 0:51from the right the height of each bar
27. 0:52indicates how long it took to render the
28. 0:54frame hover over any bar for more
29. 0:57information the real power of the micro
30. 1:00profiler though is in detailed mode
31. 1:01press contrl P or command P to pause
32. 1:04which automatically switches you to the
33. 1:05timeline from there you can left click
34. 1:08and drag to pan in any direction on a
35. 1:10modern computer with many CPU cores you
36. 1:12might need to pan up and down quite a
37. 1:14bit to find threads that are doing
38. 1:15anything at all scrolling zooms you in
39. 1:18and out with the green indicator on the
40. 1:20graph showing your zoom level to jump to
41. 1:22a particular frame right click it on the
42. 1:24graph each colored label on the timeline
43. 1:27represents a process something your
44. 1:29experien is is doing as part of
45. 1:30rendering that frame wider labels
46. 1:32represent processes that took longer to
47. 1:35complete when you see a label directly
48. 1:37underneath another label that means
49. 1:39you're looking at a child process a
50. 1:41process that runs as part of the process
51. 1:42above it because parent processes can't
52. 1:45finish until all their children do you
53. 1:47often want to troubleshoot the longest
54. 1:49running lowest level child processes if
55. 1:52you're asking what are all these
56. 1:53processes anyway me too there are
57. 1:56hundreds of them and it's hard to keep
58. 1:57them all straight so we documented the
59. 1:59most important ones at create.
60. 2:01roblox.com Link in the description if
61. 2:04the level of visual clutter is too much
62. 2:06use the groups menu to filter the list
63. 2:08of visible labels until you get to
64. 2:09something more manageable let's examine
65. 2:12a more concrete scenario generally
66. 2:14speaking we want Roblox experiences to
67. 2:16run at 60 frames per second there are
68. 2:191,000 milliseconds in a second so if we
69. 2:21divide 1,000 by 60 we can see that we
70. 2:23want a new frame every 16.67
71. 2:26milliseconds if we get 59 frames after
72. 2:2810 milliseconds and then one frame after
73. 2:31410 milliseconds that causes a huge
74. 2:33jarring stutter even though the math
75. 2:35works out to 60 FPS so consistent frame
76. 2:38times are more important than average
77. 2:40frame
78. 2:42rate this experience doesn't feel quite
79. 2:44right even though the frame rate summary
80. 2:46usually says 60 FPS if we open the micro
81. 2:49profiler we can see these frame time
82. 2:51spikes remember we want consistent frame
83. 2:53times so even at a glance right after
84. 2:55opening the micro profiler we know
85. 2:57something's wrong some frames are taking
86. 2:59way way way longer than others if we
87. 3:01examine one of the smaller frames
88. 3:02nothing jumps out but if we look at one
89. 3:04of the slow frames whoa there we can see
90. 3:07this massive process in one of the
91. 3:09worker threads and in particular a label
92. 3:11called Shady Rays the micro profiler
93. 3:13provides a lot of clues for where to
94. 3:15look Shady Rays is a script running
95. 3:17under runs service. heartbeat and the
96. 3:19problematic code seems to have to do
97. 3:21with rayc casting search for shady rays
98. 3:23in the Explorer open it and examine the
99. 3:25code we can see the same run service.
100. 3:28heartbeat event that we saw on the mic
101. 3:30profiler so we know we're on the right
102. 3:31track this script is short but if it
103. 3:33were long or complex we could wrap
104. 3:35portions of it in debug profile calls in
105. 3:37this case though the culprit seems
106. 3:39pretty clear so let's comment out the
107. 3:40function and see what
108. 3:43happens now our frames are all arriving
109. 3:45in about 16.67 milliseconds and camera
110. 3:48movement feels consistent and smooth
111. 3:51this time all we had to do was comment
112. 3:52out some code but in other cases you
113. 3:54might need to reduce the number of light
114. 3:55sources modify your environment to
115. 3:57prevent High transparency overdraw or
116. 3:59spread a particularly intensive
117. 4:01calculation across many frames for more
118. 4:03information on using the micro profiler
119. 4:05to optimize your experience check out
120. 4:07the documentation at create. roblox.com
121. 4:09thanks for watching
122. 4:17[Music]