IONICDV(7) Ionic Programmer’s Manual IONICDV(7)

ionicdv - Direct verbs for ionic devices

This provides low level access to ionic devices to perform direct operations, without general branching performed by libibverbs.

The libibverbs API is an abstract one. It is agnostic to any underlying provider specific implementation. While this abstraction has the advantage of user applications portability, it has a performance penalty. For some applications optimizing performance is more important than portability.

The ionic direct verbs API is intended for such applications. It exposes ionic specific low level operations, allowing the application to bypass the libibverbs API.

The direct include of ionic_dv.h together with linkage to the ionic library will allow usage of this new interface.

Ionic devices expose multiple UDMA pipelines. Queues can be assigned to specific pipelines by setting a UDMA mask on the protection domain before creating queues. Use ionic_dv_ctx_get_udma_count(3) and ionic_dv_ctx_get_udma_mask(3) to query the available pipelines, and ionic_dv_pd_set_udma_mask(3) to restrict queue placement.

Send and receive queues can optionally be placed in the controller memory bar for lower latency doorbell operations. Express doorbell optimizations may also be enabled. Use ionic_dv_pd_set_sqcmb(3) and ionic_dv_pd_set_rqcmb(3) to configure CMB preferences on a protection domain before creating queues.

ionic_dv_ctx_get_udma_count(3), ionic_dv_ctx_get_udma_mask(3), ionic_dv_pd_get_udma_mask(3), ionic_dv_pd_set_udma_mask(3), ionic_dv_pd_set_sqcmb(3), ionic_dv_pd_set_rqcmb(3), verbs(7)

Advanced Micro Devices, Inc.

2025-06-23 ionic