doca-rdmi

DOCA RDMA Initiator

Examples

• "DPA kernel needs to post RDMA writes to a remote responder." — this is in scope. Stay on doca_rdmi_*; do not rewrite it as host-CPU doca-rdma.
• "Function not found on doca_rdmi_ at link time."* — audit whether the symbol is EXPERIMENTAL on this DOCA before inventing a fallback API.

Instructions

Follow Loading order below. Open the tasks companion for configure / build / debug. Open the capabilities companion for RDMI vs RDMA and the experimental-symbol rule. Do not open every companion file.

Where to start: This skill assumes DOCA is already installed and the user is doing hands-on RDMI work on a host or BlueField with the DOCA package set that ships the doca-rdmi library. Open the tasks companion if the user wants to do something (install / configure / build / modify / run / test / debug / use); open the capabilities companion when the question is what can RDMI express on this version — the object model, the DPA-side handle types, the relationship to doca-rdma, the EXPERIMENTAL-tag policy, and the safety overlay.

End-to-end "walk me through doca-rdmi" questions are answerable entirely from this skill. Go straight to

end-to-end (quickref),

which carries the self-contained install-check → device/cap discovery → sample → pkg-config build → run → debug walkthrough with the exact commands. You do not need to open doca-setup or doca-programming-guide to answer an RDMI build/run/debug question. Route to doca-setup/SKILL.md when the required DOCA prerequisites are absent, partial, or version-mismatched.

Example questions this skill answers well

The CLASSES of RDMI questions this skill is built to answer, each with one worked example. The agent should treat the class as the load-bearing piece — the worked example is a single instance.

• "Should I use doca-rdmi or doca-rdma for this case?" — worked example: "I have a DPA kernel that needs to fire 1 MB RDMA writes at a remote responder; which library?". Answered by the initiator-side vs general-purpose selection rule in

  Capabilities and modes

  surface-selection table + the routing back to doca-rdma/SKILL.md when the use case is two-sided or host-CPU initiated.
• "How do I bring up an RDMI connection on the DPA datapath?" — worked example: "create a doca_rdmi_connection, attach a DPA completion context, hand the DPA-side handle to my kernel". Answered by the connection-object lifecycle in

  Capabilities and modes

  • the configure walk in

  configure.

• "How do connection and poster relate — when do I need both?" — worked example: "my application receives work requests AND posts RDMA writes; do I need a doca_rdmi_connection plus a doca_rdmi_poster, or one of them?". Answered by the two-object model in

  Capabilities and modes

  • the modify-from-sample slot table in

  modify.

• "How do I drive completions on the DPA side?" — worked example: "hook the connection to a doca_dpa_completion so my kernel polls completions directly". Answered by the DPA-side completion-attach pattern in

  Capabilities and modes

  • the run-side wiring in

  run, cross-linked into

  doca-dpa/SKILL.md for the DPA programming surface itself.
• "Is the symbol I want available — and is it stable enough to ship?" — worked example: "is doca_rdmi_poster_post GA on my installed DOCA, or still EXPERIMENTAL?". Answered by the EXPERIMENTAL-tag policy in

  Version compatibility

  • the version-discovery rule (pkg-config --modversion doca-rdmi) pinned in

  configure.

• "What does this DOCA_ERROR_* from a doca_rdmi_* call mean?" — worked example: "DOCA_ERROR_BAD_STATE from doca_rdmi_connection_dpa_completion_attach". Answered by the RDMI overlay on the cross-library taxonomy in

  Error taxonomy

  • the layered ladder in ## debug that escalates to doca-debug/SKILL.md.

Audience

This skill serves external developers building DPA-resident DOCA applications that need to initiate one-sided RDMA operations against a remote responder — i.e., users whose accelerator-side code wants to post sends, writes, or reads directly from the accelerator without round-tripping through the host CPU. The canonical caller is a DPA kernel that has been compiled with doca-dpacc-compiler and runs on the BlueField DPA datapath; a GPU-side caller that drives the DPU's RDMA queues is the sister case routed to doca-gpi/SKILL.md. This skill is not for NVIDIA developers contributing to DOCA RDMI itself, and it is not the right surface for general host-CPU two-sided RDMA — that belongs to doca-rdma/SKILL.md.

Language scope

DOCA RDMI ships as a C library with the pkg-config module name doca-rdmi. The library's host-side surface (doca_rdmi_connection_*, doca_rdmi_poster_*) is C; the DPA-side surface that the accelerator kernel uses is also C, compiled against the DOCA DPA toolchain documented in doca-dpa/SKILL.md. Other-language consumers (Rust, Go, Python, …) consume the host-side *.so through FFI; the skill's contribution in that case is to keep the connection / poster lifecycle, the EXPERIMENTAL-tag policy, the DPA-side handoff rules, and the safety overlay language-neutral, and to route the agent to the public C ABI as the authoritative surface that any wrapper will eventually call. The DPA-side surface is not wrappable in another language — it is compiled and linked into the DPA binary itself.

When to load this skill

Load this skill when the user is doing hands-on DOCA RDMI work on a host or BlueField with DOCA installed. Concretely:

• Deciding between doca-rdmi and doca-rdma for a new one-sided RDMA workload that runs from the DPA datapath.
• Creating a doca_rdmi_connection or doca_rdmi_poster, attaching a doca_dpa_completion or a doca_verbs_cq, and starting the context on the DPA datapath.
• Wiring the DPA-side handle returned by doca_rdmi_connection_get_dpa_handle / doca_rdmi_poster_get_dpa_handle into a DPA kernel that calls the matching device-side header (doca_rdmi_dev_connection.h, doca_rdmi_dev_poster.h, doca_rdmi_dev_cqe.h).
• Acknowledging receive completions on the host side via doca_rdmi_connection_recv_ack after the DPA kernel consumed them.
• Auditing which RDMI symbols are EXPERIMENTAL on the installed DOCA version, before declaring an RDMI-using component production-stable.
• Debugging a DOCA_ERROR_* returned by a doca_rdmi_* call and deciding whether the cause is a configuration mistake, a lifecycle ordering bug, an unsupported capability on this device, or a layer below DOCA.

Do not load this skill for general DOCA orientation, install of DOCA itself, or two-sided host-CPU RDMA questions. For those, use doca-public-knowledge-map/SKILL.md, doca-setup/SKILL.md, and doca-rdma/SKILL.md respectively.

What this skill provides

This is a thin loader. The body keeps only the orientation needed to pick the right next file. The substantive RDMI-specific material lives in two companion files:

• the capabilities companion — what RDMI can express on this version: the doca_rdmi_connection and doca_rdmi_poster object model, the DPA-side completion-attach pattern, the relationship to doca-verbs (RDMI builds on a doca_verbs_context) and to doca-dpa (the accelerator-side datapath), the EXPERIMENTAL-tag rule for version handling, the RDMI overlay on the cross-library DOCA_ERROR_* taxonomy, the observability surface (completion events on the PE / DPA-side completions), and the safety policy that gates posting work from an accelerator kernel into a remote responder's memory.
• the tasks companion — step-by-step workflows for the eight in-scope verbs: install, configure, build, modify, run, test, debug, use. Plus a ## rollback overlay (RDMI-specific five-step teardown for the verbs / connection / DPA-attach / MR stack) and the 5-phase universal debug-loop instantiation appended to ## debug. Plus a Deferred task verbs block that points out-of-scope questions at the right next skill.

The skill assumes a host or BlueField where DOCA is already installed at the standard location and the user has the privileges their public install profile expects. It does not cover installing DOCA itself — that path goes through doca-setup/SKILL.md.

What this skill deliberately does not ship

This skill is agent guidance, not a samples or templates bundle. To keep the boundary clean, it deliberately does not contain — and pull requests should not add:

• Pre-written DOCA RDMI application source code, in any language. The agent's job is to route the user to verified reference code on the user's installed DOCA and to prescribe a minimum-diff modification via the universal modify-a-sample workflow in doca-programming-guide/SKILL.md, layered with the RDMI-specific overrides in

  modify. Because every RDMI

  symbol is EXPERIMENTAL at the time of writing, the skill refuses to author RDMI source code from documentation prose — the API can change between releases and the resulting code may not even compile.
• Standalone build manifests (meson.build, CMakeLists.txt, Cargo.toml, …) parked inside the skill. The agent constructs the build manifest in the user's project directory against the user's installed DOCA, where pkg-config --modversion doca-rdmi is the source of truth.
• DPA-side kernel templates. The DPA-side surface is owned by doca-dpa/SKILL.md; RDMI's DPA-side headers are consumed by the DPA programming model documented there. This skill names the RDMI-specific handoff (the DPA handle type, the completion-attach call) but does not author DPA kernels.
• A samples/, bindings/, or reference/ subtree of any kind. A mock or incomplete artifact in this skill's tree, even one labeled "reference", is misleading: users will read it as buildable.

Loading order

1. Read this skill first to confirm the user's question is in scope.
2. For the RDMI object model, the DPA-side handoff pattern, the EXPERIMENTAL-tag policy, the error taxonomy, observability, and safety policy, see the capabilities companion.
3. For step-by-step workflows — install, configure, build, modify, run, test, debug, use — see the tasks companion.

Both companion files cross-link to each other and to doca-public-knowledge-map/SKILL.md whenever the right answer is "look it up in the public docs or the installed package layout" rather than "RDMI-specific guidance".

Related skills

• doca-rdma/SKILL.md — the higher-level RDMA library covering two-sided and host-CPU-initiated RDMA. RDMI is the focused initiator-side surface; doca-rdma is the right answer for the majority of RDMA use cases. The selection table in ## Capabilities and modes is the load-bearing decision aid.
• doca-dpa/SKILL.md — the DOCA DPA programming surface. RDMI returns DPA-side handles (doca_dpa_dev_rdmi_connection_t, doca_rdmi_dev_poster_t) that the DPA kernel uses through the device-side headers (doca_rdmi_dev_connection.h, doca_rdmi_dev_poster.h, doca_rdmi_dev_cqe.h); the DPA toolchain, kernel build, and execution model are owned by that skill.
• doca-gpi/SKILL.md — the GPU-side sister of this skill. GPI is the channel/queue surface a CUDA kernel uses to initiate RDMA; RDMI is the DPA-side surface. Both layer on the same DOCA RDMA / verbs substrate; either may apply depending on whether the initiator is on the DPA or on the GPU.
• doca-public-knowledge-map/SKILL.md — the routing table for every public DOCA documentation source and the on-disk layout of an installed DOCA package.
• doca-setup/SKILL.md — env preparation, install verification, and the I have no install yet path with the public NGC DOCA container.
• doca-programming-guide/SKILL.md — general DOCA programming patterns shared by every library: the canonical pkg-config + meson build pattern, the universal modify-a-shipped-sample first-app workflow, the universal Core-context lifecycle, the cross-library DOCA_ERROR_* taxonomy. This skill layers RDMI specifics on top.
• doca-debug/SKILL.md — the cross-cutting debug ladder (install / version / build / link / runtime / program / driver). RDMI-specific debug overlays on top of it.
• doca-hardware-safety/SKILL.md — the bundle-wide hardware-safety meta-policy. The ## Safety policy overlay in the capabilities companion cross-links it.
• doca-version/SKILL.md — the version detection / four-way match rule every per-artifact ## Version compatibility anchor builds on. This skill quotes the RDMI-specific overlay only.
• doca-structured-tools-contract/SKILL.md — the JSON-schema contracts for the agent-preferred structured helpers (env probe, capability snapshot, version-matrix lookup); the ## Command appendix in the tasks companion defers to them before falling back to the manual chain.