dev notes

Dev Notes

These are general free form note with pointers to good jumping to point to under stand the llama.cpp codebase.

(@<symbol> is a vscode jump to symbol code for your convenience. Also making a feature request to vscode to be able to jump to file and symbol via <file>:@<symbol>)

Where are the definitions for GGUF in llama.cpp?

GGUF file structure spec (WARN: As of 2024-06-11 the llama.cpp implementation is the canonical source for now)

All of the gguf structure can be found in gguf.c unless stated otherwise

GGUF Structure Of Interest	gguf.c reference	vscode search line
Overall File Structure	struct gguf_context	@gguf_context
File Header Structure	struct gguf_header	@gguf_header
Key Value Structure	struct gguf_kv	@gguf_kv
Tensor Info Structure	struct gguf_tensor_info	@gguf_tensor_info

Element of Interest (Think of this as an index lookup reference)

Please use this as an index not as canonical reference. The purpose of this table is to allow you to quickly locate major elements of the gguf file standard.

Header Name	GGUF Elements Of Interest	c name	c type	vscode search line
GGUF Header	Magic	magic	uint8_t[4]	gguf.c:@gguf_header
GGUF Header	Version	version	uint32_t	gguf.c:@gguf_header
GGUF Header	Tensor Count	n_tensors	uint64_t	gguf.c:@gguf_header
GGUF Header	Key Value Count	n_kv	uint64_t	gguf.c:@gguf_header
GGUF Context	Key Value Linked List	kv	gguf_kv *	gguf.c:@gguf_context
GGUF Context	Tensor Info Linked List	infos	gguf_tensor_info *	gguf.c:@gguf_context
Key Value Entry	Key	gguf_kv.key	gguf_str	gguf.c:@gguf_kv
Key Value Entry	Type	gguf_kv.type	gguf_type	gguf.c:@gguf_kv
Key Value Entry	Type	gguf_kv.value	gguf_value	gguf.c:@gguf_kv
Tensor Info Entry	Name	gguf_tensor_info.name	gguf_str	gguf.c:@gguf_tensor_info
Tensor Info Entry	Tensor shape dimension count	gguf_tensor_info.n_dim	uint32_t	gguf.c:@gguf_tensor_info
Tensor Info Entry	Tensor shape sizing array	gguf_tensor_info.ne	uint64_t[GGML_MAX_DIMS]	gguf.c:@gguf_tensor_info
Tensor Info Entry	Tensor Encoding Scheme / Strategy	gguf_tensor_info.type	ggml_type	gguf.c:@gguf_tensor_info
Tensor Info Entry	Offset from start of 'data'	gguf_tensor_info.offset	uint64_t	gguf.c:@gguf_tensor_info

Also just note that these values are not actually part of gguf but is there for internal usage and is calculated during model loading. Aka it's for the writing/reading api.

Header Name	GGML Elements Of Interest	c name	c type	vscode search line
GGUF Context	Alignment	alignment	size_t	gguf.c:@gguf_context
GGUF Context	Offset Of 'Data' From Beginning Of File	offset	size_t	gguf.c:@gguf_context
GGUF Context	Size Of 'Data' In Bytes	size	size_t	gguf.c:@gguf_context
Tensor Info Entry	Tensor memory mapped pointer location in computer	data	void *	gguf.c:@gguf_tensor_info
Tensor Info Entry	Tensor memory mapped size of layer data in computer	size	size_t	gguf.c:@gguf_tensor_info

Is there a simple example of gguf being used?

There is this cpp example program that will write a test gguf write/read

• ./example/gguf.cpp