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doca-pcc-ztr-rttcc-algo

Deploys and tunes the DOCA ZTR RTTCC reference congestion-control algorithm on BlueField-3 DPAs.

3.2k|370|Updated Feb 25, 2026
Search Tags:#doca#dpa#pcc#congestion control#dpacc#roce-v2#bluefield-3
One-click install
npx skills add https://github.com/NVIDIA/skills --skill doca-pcc-ztr-rttcc-algo
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: doca-pcc-ztr-rttcc-algo
Source: https://github.com/NVIDIA/skills/tree/main/skills/doca-pcc-ztr-rttcc-algo
Command: npx skills add https://github.com/NVIDIA/skills --skill doca-pcc-ztr-rttcc-algo

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Deploying NVIDIA's shipped Zero-Touch RoCE RTT-based Congestion Control (ZTR RTTCC) reference algorithm on a BlueField-3 DPA requires precise in-place edits to the DOCA PCC sample application, correct DPACC build-time variant selection, and disciplined parameter tuning — mistakes can throttle production RoCE-v2 traffic or leave the algorithm loaded but ineffective.

Core Features & Use Cases

  • Sample Integration Guidance: Walks the exact in-place edits to rp_rtt_template_dev_main.c, build_device_code.sh, and dependencies/meson.build that wire doca_pcc_dev_ztr_rttcc_algo into the shipped DOCA PCC application.
  • Variant Selection & Parameter Tuning: Explains the compile-time variant set (vanilla, path-migration, RX-rate, multipath, window-probeless) and the host-set parameter workflow via doca_pcc_dev_set_ztr_rttcc_params without rebuilding the DPA image.
  • Diagnosis & Observability: Provides a layered debug ladder for DOCA_PCC_DEV_STATUS_FAIL errors and the "loaded but counters are flat" failure mode, routing counter inspection to doca-pcc-counters.
  • Use Case: An operator with a BlueField-3 carrying production RoCE-v2 traffic from a GPU cluster asks whether the shipped algorithm is a suitable baseline, then deploys it, confirms it shapes flows under load, and tunes latency-sensitive parameters.

Quick Start

Ask your agent to help you deploy and tune the DOCA-shipped ZTR RTTCC reference algorithm on your BlueField-3 port carrying RoCE-v2 traffic.

Frequently Asked Questions about doca-pcc-ztr-rttcc-algo

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I deploy the DOCA ZTR RTTCC algorithm on a BlueField-3 DPA?▼

Patch the shipped DOCA PCC sample by including doca_pcc_dev_ztr_rttcc_algo.h, dispatching from doca_pcc_dev_user_algo(), initializing in doca_pcc_dev_user_init(), adding -ldoca_pcc_ztr_rttcc_algo_dev to build_device_code.sh, then rebuilding with meson and ninja.

How do I tune ZTR RTTCC parameters without rebuilding the DPA image?▼

Apply parameter updates from the host through doca_pcc_dev_set_ztr_rttcc_params, which range-checks each value before applying. Quote parameter identifiers verbatim from the installed DPA-side headers; a DOCA_PCC_DEV_STATUS_FAIL means no parameters were changed.

Which ZTR RTTCC variant should I choose for multipath RoCE-v2 deployments?▼

The DPA-side source ships vanilla, path-migration, RX-rate, multipath, multipath with credits, and window-probeless variants. Selection happens at DPACC build time, so switching variants requires rebuilding both the DPA-side image and the host application.

Why is the PCC algorithm loaded but my RoCE-v2 flows are unchanged?▼

Flat counters usually mean no CC events reach the algorithm's slot, the doca_pcc context is attached to the wrong port, or no RoCE-v2 traffic exists on the port. Inspect per-port and per-flow counters with doca-pcc-counters before suspecting an algorithm bug.

When should I write a custom PCC algorithm instead of using ZTR RTTCC?▼

Use the shipped reference as the no-config baseline unless your latency, fairness, or convergence requirements diverge from RTT-based control. Custom algorithms are written against the host-side doca-pcc framework and the public DOCA PCC programming guide, not this skill.

What are the prerequisites for running the ZTR RTTCC algorithm?▼

You need DOCA SDK installed at /opt/mellanox/doca, a BlueField-3 exposing the DPA processor, the firmware custom-PCC slot enabled, a DPACC compiler version-matched to DOCA, and live RoCE-v2 traffic on the attached port.

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