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> * To convert Linux kernel subsystems into Python so I can quickly understand them (I'm a C programmer but everyone reads Python faster). Do you have an examp

> * To convert Linux kernel subsystems into Python so I can quickly understand them (I'm a C programmer but everyone reads Python faster). Do you have an example chat of this output? Sounds interesting. Do you just dump the C source code into the prompt and ask it to convert to Python?

tptacek 2y ago
No, ChatGPT is way cooler than that. It's already read every line of kernel code ever written. I start with a subsystem: the device mapper is a good recent example. I ask things like "explain the linux device mapper. if it was a class in an object-oriented language, what would its interface look like?" and "give me dm_target as a python class". I get stuff like: def linear_ctr(target, argc, argv): print("Constructor called with args:", argc, argv) # Initialize target-specific data here return 0 def linear_dtr(target): print("Destructor called") # Clean up target-specific data here def linear_map(target, bio): print("Mapping I/O request") # Perform mapping here return 0 linear_target = DmTarget(name="linear", version=(1, 0, 0), module="dm_mod") linear_target.set_ctr(linear_ctr) linear_target.set_dtr(linear_dtr) linear_target.set_map(linear_map) info = linear_target.get_info() print(info) (A bunch of stuff elided). I don't care at all about the correctness of this code, because I'm just using it as a roadmap for the real Linux kernel code. The example use case code is an example of something GPT 4o provides that I didn't even know I wanted.
- throwup238 2y ago
  That's awesome. Have you tried asking it to convert Python (psuedo-ish) code back into C that interfaces with the kernel?
  - tptacek 2y ago
    No, but only because I have no use for it. I wouldn't be surprised if it did a fine job! I'd be remiss if I didn't note that it's way better at doing this for the Linux kernel than with codebases like Zookeeper and Kubernetes (though: maybe o1 makes this better, who knows?). I do feel like someone who skipped like 8 iPhone models (cross-referencing, EIEIO, lsp-mode, code explorers, tree-sitter) and just got an iPhone 16. Like, nothing that came before this for code comprehension really matters all that much?
- INGSOCIALITE 2y ago
  it's all placeholders - that's my experience with gpt trying to write slop code
  - throwup238 2y ago
    Those are placeholders for user callbacks passed to the device mapper subsystem. It’s a usage example not implementation code.
  - jeffhuys 2y ago
    Then ask it to expand. Be specific.
    - tptacek 2y ago
      I wasn't about to paste 1000 lines of Python into the thread; I just picked an interesting snippet.

tptacek 2y ago

No, ChatGPT is way cooler than that. It's already read every line of kernel code ever written. I start with a subsystem: the device mapper is a good recent example. I ask things like "explain the linux device mapper. if it was a class in an object-oriented language, what would its interface look like?" and "give me dm_target as a python class". I get stuff like: def linear_ctr(target, argc, argv): print("Constructor called with args:", argc, argv) # Initialize target-specific data here return 0 def linear_dtr(target): print("Destructor called") # Clean up target-specific data here def linear_map(target, bio): print("Mapping I/O request") # Perform mapping here return 0 linear_target = DmTarget(name="linear", version=(1, 0, 0), module="dm_mod") linear_target.set_ctr(linear_ctr) linear_target.set_dtr(linear_dtr) linear_target.set_map(linear_map) info = linear_target.get_info() print(info) (A bunch of stuff elided). I don't care at all about the correctness of this code, because I'm just using it as a roadmap for the real Linux kernel code. The example use case code is an example of something GPT 4o provides that I didn't even know I wanted.

throwup238 2y ago
That's awesome. Have you tried asking it to convert Python (psuedo-ish) code back into C that interfaces with the kernel?
- tptacek 2y ago
  No, but only because I have no use for it. I wouldn't be surprised if it did a fine job! I'd be remiss if I didn't note that it's way better at doing this for the Linux kernel than with codebases like Zookeeper and Kubernetes (though: maybe o1 makes this better, who knows?). I do feel like someone who skipped like 8 iPhone models (cross-referencing, EIEIO, lsp-mode, code explorers, tree-sitter) and just got an iPhone 16. Like, nothing that came before this for code comprehension really matters all that much?
INGSOCIALITE 2y ago
it's all placeholders - that's my experience with gpt trying to write slop code
- throwup238 2y ago
  Those are placeholders for user callbacks passed to the device mapper subsystem. It’s a usage example not implementation code.
- jeffhuys 2y ago
  Then ask it to expand. Be specific.
  - tptacek 2y ago
    I wasn't about to paste 1000 lines of Python into the thread; I just picked an interesting snippet.