MLX4DV(7)

🌸 MLX4DV 🌸

ok so this is MLX4DV(7) from the Miscellaneous Information Manual, section 7 — direct verbs, but make it low level, bestie 💅

✨ NAME ✨

mlx4dv — direct verbs for mlx4 devices, fr fr 🦋

This is low level access to mlx4 devices so you can do data path operations, without all that general branching that ibv_post_send(3) is out here doing. no cap.

💖 DESCRIPTION 💖

okay so, plot twist: the libibverbs API is an abstract one. it literally does not care about whatever provider-specific implementation is underneath. and that abstraction? it's giving portability. your user applications can move around, cute. but it comes with a performance penalty 😭 and for some applications, optimizing performance matters more than portability. iykyk.

the mlx4 direct verbs API is for exactly those applications. it exposes mlx4 specific low level data path (send / receive / completion) operations, letting the application bypass the libibverbs data path API entirely. main character energy honestly 👑

this interface consists of one hardware specific header file with the relevant inline functions, plus the conversion logic from ibverbs structures to mlx4 specific structures. periodt.

so the direct include of mlx4dv.h together with linkage to the mlx4 library will allow usage of this new interface. that's it, that's the combo 🎀

once an application uses the direct flow, the locking scheme is fully managed by itself. and there's an expectation that no mixed flows in the data path for both direct/non-direct access will be by the same application. so like, pick a lane bestie 💀

🫶 heads up: no mixed direct + non-direct data path flows from one application. that's the vibe rule, not a suggestion.

📝 NOTES 📝

ngl this section is empty in the original. nothing here. it's just vibes and silence 🙈✨ (iconic of it, honestly)

🔍 SEE ALSO 🔍

• ibv_post_send(3)
• verbs(7)

👑 AUTHORS 👑

Maor Gottlieb <maorg@mellanox.com> — thank you for your service, king 🫡💜

and that's a wrap! this page is version 1.0.0, dated 2017-04-19, and it lives in the MLX4DV(7) section of the manual. slay, go read mlx4dv.h now 🌈⭐