DOCA PCC Counters (pcc_counters.sh)

Where to start: This is a tool skill for invoking pcc_counters.sh — a small bash script that arms and reads the device's fixed set of firmware / hardware PCC diagnostic counters (CNP count, RTT-perf, WRED-drop, RTT-gen, handled events) through the mlx5 debugfs diag_cnt interface. Open TASKS.md and start at ## run for the canonical set-then-query sequence, or ## debug when the user reports "`ERROR: Bad Device`", "counter stuck at zero", or "the dump is empty". Open CAPABILITIES.md when the question is which counters the script reports and how it reaches them. If the user has not installed DOCA / MFT yet, route to doca-setup first.

This skill is the firmware / HW PCC counter readout surface. It is NOT the host-side control library that loads custom congestion-control kernels onto the DPA (that is doca-pcc) and it is NOT the firmware PCC algorithm configuration (that path is firmware configuration, routed via doca-public-knowledge-map). The counters this script reads are device / firmware diagnostic counters that exist regardless of whether a custom doca-pcc DPA kernel is running — do not condition them on a custom kernel being loaded.

Example questions this skill answers well

The CLASSES of pcc_counters.sh 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 do I read the PCC diagnostic counters on this

device?" — worked example: "arm and dump the CNP / RTT / WRED-drop counters for `/dev/mst/mt41692_pciconf0`". Answered by the fixed counter set in CAPABILITIES.md ## Capabilities and modes + the set-then-query invocation in TASKS.md ## run.

• "What is the smallest legal invocation?" — worked

example: "what exactly do I type?". Answered by the two-positional-argument contract (set | query + an mst device path) in TASKS.md ## run.

• "The script printed ERROR: Bad Device — what's wrong?"

— worked example: "my device path is not matching". Answered by the device-resolution layer in CAPABILITIES.md ## Error taxonomy + TASKS.md ## debug.

• "A counter is stuck at zero — is the device idle, the

counters not armed, or genuinely no events?" — worked example: "`PCC_CNP_COUNT` reads 0 after `query`". Answered by the arm-before-read rule and the layered diagnosis in TASKS.md ## debug + CAPABILITIES.md ## Error taxonomy.

• "Is this script on my install, and where?" — worked

example: "is `pcc_counters.sh` present and where does the install put it". Answered by the install overlay in CAPABILITIES.md ## Version compatibility, which redirects to the canonical doca-version rules.

Audience

This skill serves operators, developers, and AI agents who need to read a ConnectX / BlueField device's firmware PCC diagnostic counters to reason about congestion-control behaviour (CNP generation, RTT requests/responses, WRED drops) on a port. Concretely:

• A network operator confirming whether congestion-control

events (CNPs, RTT, WRED drops) are occurring on a device.

• A developer correlating a custom doca-pcc algorithm's

effect with the device-level PCC diagnostic counters (the script reads the firmware counters; the custom algorithm itself is a separate surface owned by doca-pcc).

• An AI agent producing a PCC counter snapshot as evidence

for a congestion-control investigation.

It is not for users debugging the script's bash itself, not the place to learn how to write a custom PCC algorithm — that audience belongs in doca-pcc — and not the place for users who want to configure the factory firmware PCC algorithm (route via doca-public-knowledge-map).

pcc_counters.sh is shipped as a plain bash script installed under the DOCA tools directory (per install_data in tools/pcc_counters/meson.build), not a compiled binary and not a library you link against. The skill uses the bundle's kind: tool three-file shape (SKILL.md + CAPABILITIES.md + TASKS.md) so the agent's task-verb contract (configure / build / modify / run / test / debug) is uniform across the bundle.

When to load this skill

Load this skill when the user is — or the agent needs to — arm and read the device PCC diagnostic counters on a host or BlueField Arm with the mst tools available and debugfs mounted. Concretely:

• Arming the diagnostic counters with set on a target mst

device.

• Reading the armed counters with query and quoting the

named counter lines verbatim.

• Capturing a counter readout as evidence for a

congestion-control investigation.

Do not load this skill for general DOCA orientation, custom-PCC algorithm design, the host-side doca-pcc library API, the factory firmware PCC algorithm, or DOCA / MFT install. For those, route to doca-public-knowledge-map, doca-pcc, or doca-setup.

What this skill provides

This is a thin loader. Substantive material lives in two companion files:

• CAPABILITIES.md — what pcc_counters.sh does: the exact

two-operation surface (set arms the device's diagnostic counters by writing counter IDs + params to debugfs; query reads the diag_cnt/dump and prints the named counters), the FIXED firmware / HW counter set it knows (PCC_CNP_COUNT, the MAD_RTT_PERF_CONT_*, the *_EVENT_WRED_DROP family, HANDLED_*_EVENTS, the DROP_RTT_PORT*/RTT_GEN_PORT* families), how it resolves an mst device to a PCI address (mst status -v + lspci) and reaches /sys/kernel/debug/mlx5/<pci>/diag_cnt/, the install-availability overlay that redirects to doca-version, the layered error taxonomy (script-not-present / bad-device / not-armed-before-query / debugfs-or-permission / counter-stuck-at-zero / cross-cutting), and the safety policy that flags set as a privileged debugfs write and any CC tuning decision derived from a reading as high-stakes.

• TASKS.md — step-by-step workflows for the in-scope task

verbs: configure (route to install + confirm mst / debugfs / sudo), build (route to install; nothing to compile — it is a script), modify (refuse — do not patch the shipped script), run (the set-then-query sequence), test (confirm the dump contains the named counters with finite values), debug (the layered diagnosis ladder), plus a Deferred task verbs block and a Command appendix.

The skill assumes a host or BlueField where DOCA / MFT is already installed (mst tools present, debugfs mounted, sudo available) and the target device is visible to mst status -v.

What this skill deliberately does not ship

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

• Invented flags or subcommands. pcc_counters.sh has

exactly two operations (set, query), takes exactly two positional arguments, and has NO --help, --version, list, snapshot, watch, or diff. Do not invent any.

• Pre-baked example counter values. Counter values are

device-, firmware-, and traffic-state-specific; a captured value will mislead an operator on a different device.

• Wrappers, parsers, or rewritten copies of the script.

The script is the contract; modifying or re-implementing it is out of scope.

• A specific congestion-control tuning recommendation

derived from a counter reading. That is a high-stakes domain question — the skill prescribes how to capture the counters; it refuses to translate a delta into a CC parameter change without the user's own domain analysis.

• A samples/ or reference/ subtree. This is a thin

loader for a documented script; substantive material lives in the script and the public PCC documentation.

Loading order

1. Read this SKILL.md first to confirm the user's question

is in scope (reading the device's firmware PCC diagnostic counters; not designing or loading a custom algorithm).

1. For what the script does, the fixed counter set, the

debugfs mechanism, the install-availability overlay, the layered error surface, and the safety posture, see CAPABILITIES.md.

1. For the documented invocations — configure, build,

modify, run, test, debug, plus the Command appendix — see TASKS.md.

Related skills

• doca-pcc — the host-side

library for writing and loading custom congestion-control kernels onto the DPA. It is a SEPARATE surface: the firmware PCC diagnostic counters pcc_counters.sh reads exist independently of any custom doca-pcc kernel, but an operator tuning a custom algorithm may read these counters to observe device-level CC behaviour. Conflating the script (firmware counter readout) with the library (custom algorithm load/control) is the most common PCC first-touch error.

• doca-public-knowledge-map

— routing to the public DOCA / PCC documentation set, including the firmware PCC algorithm configuration.

• doca-version — canonical

DOCA version-handling rules. The ## Version compatibility section in CAPABILITIES.md is a concise overlay that redirects here.

• doca-setup — env preparation,

install verification, mst tools, debugfs, and the I have no install yet path with the public NGC DOCA container. This skill assumes its preconditions are satisfied.

• doca-debug — the

cross-cutting debug ladder. The PCC counter readout slots in as a read-only device-state evidence source before any congestion-control tuning recommendation is made.

• doca-programming-guide

— general DOCA programming patterns shared across the bundle.