46 lines
3.3 KiB
Plaintext
46 lines
3.3 KiB
Plaintext
[video output=day325 member=cmuratori stream_platform=twitch stream_username=handmade_hero project=code title="Ticket Mutexes" vod_platform=youtube id=A2kCmouscjM annotator=Miblo annotator=AsafGartner]
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[0:23][Recap and set the stage for the day]
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[1:31][Blackboard: Ticket Taking]
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[4:11][Blackboard: Singly-linked list]
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[6:45][Blackboard: A way to atomically add to a linked list]
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[7:44][Blackboard: Removing from a list]
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[9:36][Blackboard: Multithreaded addition to linked lists]
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[11:46][Blackboard: Multithreaded removal from linked lists]
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[13:29][Blackboard: Ticket Taking as a way to implement a fast, simple mutex for little chunks of code]
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[14:37][Blackboard: Atomic compare exchange[ref
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site="Maurice Herlihy"
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page="Wait-Free Synchronization"
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url="https://cs.brown.edu/~mph/Herlihy91/p124-herlihy.pdf"]]
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[17:41][Blackboard: Atomic increment]
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[19:02][Blackboard: Ticket Taking and Mutex (mutual exclusion)]
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[22:57][Blackboard: volatile int mutex][quote 518]
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[27:39][Blackboard: Annoyingly, this implementation provides no guarantee that any thread will ever get a turn]
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[30:04][Blackboard: Ticket Taking as a way to ensure that threads get retired in order]
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[35:12][handmade_shared.h: Introduce struct ticket_mutex, BeginTicketMutex() and EndTicketMutex()]
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[39:37][handmade_asset.cpp: Implement AddOp()]
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[42:49][handmade_platform.h: Introduce and add a platform_texture_op_queue to the game_memory struct for AddOp() to use]
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[45:48][handmade_asset.cpp: Consider not setting Work->Asset->State in LoadAssetWorkDirectly()]
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[47:21][handmade_asset.cpp: Continue implementing AddOp()]
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[49:56][handmade_platform.h: Move the ticket mutex in from handmade_shared.h]
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[51:23][Consider building separate lists for each threads inside task_with_memory]
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[52:25][handmade_asset.cpp: Add platform_texture_op_queue to load_asset_work and pass it to the necessary functions]
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[55:54][Run the game and hit the assertion in AddOp()]
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[56:12][win32_handmade.cpp: Make WinMain() populate the TextureOps free list]
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[58:53][handmade_opengl.cpp: Make OpenGLManageTextures() return a texture_op]
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[59:37][win32_handmade.cpp: Make WinMain() call OpenGLManageTextures() inside a mutex]
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[1:01:15]["You ALMOST only live once"][quote 519]
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[1:04:49][Run the game and see that it almost worked]
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[1:05:06][Q&A][:speech]
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[1:05:50][handmade_asset.cpp: Note that we haven't dealt with Work->Asset->State]
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[1:07:07][@dmitsuki][Handmade Vulkan renderer when?]
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[1:07:21][@ezysigh][Do you need a safety write barrier before the current ticket increment (inside mutex_unlock)?]
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[1:09:07][@phort99][Do you use an sRGB framebuffer and / or premultiplied alpha?]
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[1:10:20][win32_handmade.cpp: Remove Win32GetThreadStartupForGL()]
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[1:11:24][Run the game and note that our texture loading bug is 100% reproducible]
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[1:12:01][@phort99][Can you explain about the secondary framebuffer not being premultiplied? What's the secondary framebuffer for?]
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[1:13:05][@caviar_liberta][And it might be pointless to do but, since you are using C++, have you used any ASM calls inside your code?]
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[1:14:23][@baramordax][Is there a reason you're not using scoped mutex guards that handle unlocking whenever the guard goes out of scope?]
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[1:14:38][win32_handmade.cpp: Demo the difference between our mutex and a scoped mutax guard]
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[1:17:48][Wrap it up with a few words on what is likely going wrong with the texture loading][:speech]
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[/video]
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