Threading Successes of
Popular PC Games and Engines
Paul Lindberg and Brad Werth
Intel Corporation
GDC 2008
What’s this all about?
•Last year we had a great turnout for our
hands-on tutorial on game threading.
•This year we want to focus on current
commercial products and future pathfinding
efforts.
•We’ll cover performance and feature
enhancements from threading.
•This is a half day tutorial!
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What we’ll hit today
•Introduction
•Supreme Commander
•Gamebryo Element Engine
•Hellgate: London
– Break!
•Intel’s n-core engine experiment
•Allegorithmic’s Substance
•Wrap-up
– Food!
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Why threading?
•GHz era – so over.
•Multi-core is ubiquitous in gaming
platforms.
•Consumers demand validation of their
purchase.
•Threading is still an unsolved problem for
games.
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Let’s look at common threading
themes for games
• Task (on a thread)
Task
• Control Transition
– Lock protecting shared data
– Data copied to local data
– Operation on local data
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Render Split works well, but gains
are limited
Render
The Rest
• Copy data necessary for calls to rendering APIs
• Make all rendering calls from the same thread
• Render one frame behind the simulation
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Work Crew or Pipeline moves a lot
of data around
Particles
Particles
Particles
Particles
Render
Particles
Render
Animation
Animation
Animation
Animation
Physics
Physics
Physics
Physics
AI
AI
• Apply the Render Split concept everywhere
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Operation Queue keeps data
localized, and bandwidth down
Physics
AI
Queue
Render
Service
Animation
• Keep the data in one place, but queue up
operations on it
• In a perfect world, reads are immediate, free, and
consistent
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How are games today targeting
multi-core?
• Thread for performance
– Framerate
– Load times
– Easier path to smooth framerates, compared to time-slicing
– Now very common
• Thread for features
– Many possible CPU-intensive effects
– Just starting to appear
• Use threaded middleware
– Does whatever it does, and scales it out
– Common, but how well do they work together?
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