A Mental Model of CPU Performance — Handmade Hero — Episode Guide

2:17Blackboard: Optimization

3:58Blackboard: CPU + GPU instructions

5:28Blackboard: Math operations done wide (SIMD)

8:26Blackboard: An example instruction

10:10Blackboard: Issuing an instruction is expensive

13:13Blackboard: Optimization considerations

15:56Blackboard: Memory access costs

17:54Blackboard: Cycles

22:05Blackboard: You should always know how many cycles you have to work with

24:37Blackboard: You won't always have all cycles available for use

25:57Blackboard: What is a cycle?

31:38Blackboard: Pipeline stages

34:36Blackboard: Why pipeline? (Doing the laundry)

39:41Blackboard: Latency and Throughput

43:53Blackboard: Where latency causes us a problem

48:33Blackboard: Cache miss

51:01Blackboard: Hyperthreading

52:42Blackboard: Optimization, the platform

55:07Blackboard: So that is optimization^α

55:25Blackboard: Efficiency

59:30Q&A

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59:30Q&A

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59:30Q&A

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1:00:13atomiclich Would you be willing to make more blackboard episodes? This is very informative

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1:00:13atomiclich Would you be willing to make more blackboard episodes? This is very informative

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1:00:13atomiclich Would you be willing to make more blackboard episodes? This is very informative

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1:00:46grumpygiant256 Are you going to be using anything like VTune for measuring performance?

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1:00:46grumpygiant256 Are you going to be using anything like VTune for measuring performance?

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1:00:46grumpygiant256 Are you going to be using anything like VTune for measuring performance?

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1:01:26bakeheart How are instructions written in cache memory?

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1:01:26bakeheart How are instructions written in cache memory?

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1:01:26bakeheart How are instructions written in cache memory?

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1:02:33d7samurai Do we manually issue prefetching or is that something inferred by the CPU by looking at how we access memory?

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1:02:33d7samurai Do we manually issue prefetching or is that something inferred by the CPU by looking at how we access memory?

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1:02:33d7samurai Do we manually issue prefetching or is that something inferred by the CPU by looking at how we access memory?

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1:05:08childz I know this is a long way off, but after Handmade Hero is done, do you plan to continue educational streams?

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1:05:08childz I know this is a long way off, but after Handmade Hero is done, do you plan to continue educational streams?

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1:05:08childz I know this is a long way off, but after Handmade Hero is done, do you plan to continue educational streams?

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1:05:34andsz_ How often do you estimate the actual amount of work prior to implementing a feature vs just implementing it and measuring it?

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1:05:34andsz_ How often do you estimate the actual amount of work prior to implementing a feature vs just implementing it and measuring it?

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1:05:34andsz_ How often do you estimate the actual amount of work prior to implementing a feature vs just implementing it and measuring it?

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1:08:59snobrdr97 So if memory takes a few hundred cycles if the instructions have to reach out to the hard drive, what impact would that have?

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1:08:59snobrdr97 So if memory takes a few hundred cycles if the instructions have to reach out to the hard drive, what impact would that have?

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1:08:59snobrdr97 So if memory takes a few hundred cycles if the instructions have to reach out to the hard drive, what impact would that have?

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1:11:14starchypancakes Two questions: 1) Are there ever any cases where we have to worry about one of our instructions being decoded into multiple microcode instructions without our knowledge?

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1:11:14starchypancakes Two questions: 1) Are there ever any cases where we have to worry about one of our instructions being decoded into multiple microcode instructions without our knowledge?

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1:11:14starchypancakes Two questions: 1) Are there ever any cases where we have to worry about one of our instructions being decoded into multiple microcode instructions without our knowledge?

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1:13:16starchypancakes 2) In optimizing, have you set up the code in such a way that you can optimize things function-by-function with this eventuality in mind, or will we have to restructure some of the functions to allow them to be optimized?

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1:13:16starchypancakes 2) In optimizing, have you set up the code in such a way that you can optimize things function-by-function with this eventuality in mind, or will we have to restructure some of the functions to allow them to be optimized?

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1:13:16starchypancakes 2) In optimizing, have you set up the code in such a way that you can optimize things function-by-function with this eventuality in mind, or will we have to restructure some of the functions to allow them to be optimized?

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1:16:37hyco24 Would it be inefficient to offload the cache to an SSD over/or with minimal RAM usage or would the latency be too much?

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1:16:37hyco24 Would it be inefficient to offload the cache to an SSD over/or with minimal RAM usage or would the latency be too much?

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1:16:37hyco24 Would it be inefficient to offload the cache to an SSD over/or with minimal RAM usage or would the latency be too much?

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1:17:32vertex_ "Premature Optimization is the root of all evil." What's your take on that quote?

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1:17:32vertex_ "Premature Optimization is the root of all evil." What's your take on that quote?

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1:17:32vertex_ "Premature Optimization is the root of all evil." What's your take on that quote?

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1:19:28noxy_key Is there any way to use or avoid hyperthreading to your advantage?

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1:19:28noxy_key Is there any way to use or avoid hyperthreading to your advantage?

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1:19:28noxy_key Is there any way to use or avoid hyperthreading to your advantage?

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1:19:44zjadekkarenvae What do you tell someone who doesn't like emacs?

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1:19:44zjadekkarenvae What do you tell someone who doesn't like emacs?

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1:19:44zjadekkarenvae What do you tell someone who doesn't like emacs?

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1:20:39bakeheart Does hyperthreading reduce maximum bandwidth because it has to switch between states, or can both states operate at the same time?

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1:20:39bakeheart Does hyperthreading reduce maximum bandwidth because it has to switch between states, or can both states operate at the same time?

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1:20:39bakeheart Does hyperthreading reduce maximum bandwidth because it has to switch between states, or can both states operate at the same time?

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1:21:20quatzequatel In your experience what drives the "good enough" optimization and how do the novice guys get a handle on that?

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1:21:20quatzequatel In your experience what drives the "good enough" optimization and how do the novice guys get a handle on that?

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1:21:20quatzequatel In your experience what drives the "good enough" optimization and how do the novice guys get a handle on that?

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1:24:00Wrap things up

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1:24:00Wrap things up

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1:24:00Wrap things up

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