Design proposal for new ring buffer API #3848
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mikeagun
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dthaler,
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Alan-Jowett,
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rectified95
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mikeagun
changed the title
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Converting to draft while I make a few design updates. |
Splits the design so callback consumers use the existing libbpf APIs, and mapped memory consumers use the new windows-specific functions.
docs/RingBuffer.md
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| * | ||
| * @returns Pointer to consumer offset | ||
| */ | ||
| uint64_t* rb__consumer_offset(void *cons); |
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Does this exact same prototype exist on Linux? I couldn't find it, I could only find
https://github.com/torvalds/linux/blob/master/include/uapi/linux/bpf.h#L4558 as a helper function.
This doesn't follow https://github.com/microsoft/ebpf-for-windows/blob/main/docs/DevelopmentGuide.md#coding-conventions so is only ok if it's identical to Linux.
docs/RingBuffer.md
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| * | ||
| * @returns Pointer to producer offset | ||
| */ | ||
| volatile const uint64_t* rb__producer_offset(volatile const void *prod); |
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Does this exact same prototype exist on Linux? I couldn't find it, I could only find
https://github.com/torvalds/linux/blob/master/include/uapi/linux/bpf.h#L4558
| * | ||
| * @returns Wait handle | ||
| */ | ||
| HANDLE ebpf_ring_buffer_get_wait_handle(fd_t map_fd); |
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| HANDLE ebpf_ring_buffer_get_wait_handle(fd_t map_fd); | |
| ebpf_handle_t ebpf_ring_buffer_get_wait_handle(fd_t map_fd); |
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Same question as above, can I get multiple handles? Do I need to close this?
| * @retval EBPF_SUCCESS The operation was successful. | ||
| * @retval other An error occurred. | ||
| */ | ||
| ebpf_result_t ebpf_ring_buffer_get_buffer(fd_t map_fd, _Out_ void **producer, _Out_ void **consumer); |
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Does this return the same buffer every time it's called? How long is the mapping valid for? Until the fd is closed?
| pages mapped into user space, and `ebpf_ring_buffer_get_wait_handle()` to get the SynchronizationEvent (auto-reset) KEVENT | ||
| to use with `WaitForSingleObject`/`WaitForMultipleObject`. | ||
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| Similar to the linux memory layout, the first page of the producer and consumer memory is the "producer page" and "consumer page", |
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Are you going to document the layout, or are users required to use the C helpers to retrieve offsets?
Description
Add docs/RingBuffer.md with proposal for new ebpf ring buffer map API exposing mapped memory so consumers can directly read the records written by the producer (similar to linux mmap/epoll style ring buffer consumer).
Testing
N/A
Documentation
Documentation only.
Installation
N/A