Agent skill · software engineering · nvidia
doca-spcx-cc
Use this skill when the user is invoking `doca_spcx_cc` (the host-side CLI under /opt/mellanox/doca/tools/) to load, parameterize, start, observe, or stop an SPC-X congestion-control algorithm on a BlueField with a DPA processor against a live RDMA / RoCE fabric, or picking SPCX vs the established `doca-pcc` surface. Trigger even when the user does not say "DOCA SPCX" or "doca_spcx_cc" — typical implicit phrasings include "I want to write a custom RTT-based CC algorithm for my RoCE fabric", "my SPCX session loaded but throughput / latency didn't change", "doca_pcc status shows Active but factory CC seems to still be in charge", "DOCA_PCC_PS_ERROR on start", "is the programmable-CC surface available on my install", or "DPA-side algorithm image won't load". Refuse and route elsewhere for DPA-side algorithm authoring detail, factory PCC firmware configuration, read-only PCC counter inspection, raw DPA cycle profiling, RDMA library programming, or general DOCA install — those belong to other skills.
Why this skill is useful
Provides specific commands and workflows for managing SPCX algorithms on RDMA/RoCE fabrics that the AI wouldn't reliably generate on its own.
What it needs
Requires doca-sdk installed locally. About 10k tokens when loaded. Last updated 2026-08-07. 2,816 stars on the source repository.
What this skill does
DOCA SPCX Congestion-Control Tool Examples "Should I use SPCX or doca-pcc for a custom CC algorithm?" — this is in scope. Walk the decision tree before loading anything on a live fabric. "SPCX loaded but throughput did not change." — confirm the algorithm is in charge before retuning parameters. Instructions Follow Loading order below. Open the tasks companion for configure / run. Open the capabilities companion for the SPCX-vs-PCC tradeoff and safety. Do not open every companion file. Where to start: This is a tool skill for invoking docaspcxcc — the host-side CLI that exercises an SPC-X congestion-control algorithm on a live RDMA / RoCE fabric driven by a BlueField with a DPA processor. Open the tasks companion and start at configure for the SPCX-vs-PCC-vs-factory-firmware decision tree (load-bearing gate before any code), the role decision (RP / NP), the DPA-side algorithm authoring vs consumption split, and the live-link / contention precondition. Open the capabilities companion when the question is what does SPCX let me express that doca-pcc does not, what is the SPCX-vs-PCC tradeoff, what runtime metrics does the tool surface, or what is the safety posture for loading a custom CC algorithm on a production fabric. If DOCA is not installed yet, route to doca-setup/SKILL.md first. This skill covers the SPC-X CC tool. doca-pcc/SKILL.md is the established PCC story; SPCX is the documented extension that authors SPCX-class algorithms on the same DPA hardware substrate. The zero-touch RTT-based CC algorithm (ZTR-RTT) is one NVIDIA reference algorithm that can be loaded through either the PCC or SPCX path depending on the install and the user's algorithm choice; the agent surfaces this decision tree explicitly per the capabilities companion. Example questions this skill answers well The CLASSES of docaspcxcc questions this skill is built to answer, each with one worked example. The class is the load-bearing piece; the worked example is one instance. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills nvidia/doca-spcx-cc