Modular QoS Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Release

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Modular QoS Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Release

Global statistics counters for Priority Flow Control and Priority Flow Control watchdog

Updated: June 9, 2026

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Global statistics counters consolidate Priority Flow Control (PFC) and PFC Watchdog data across all interfaces, providing a unified view of congestion and pause activity.

A global statistics counter for Priority Flow Control (PFC) and PFC watchdog is an observability mechanism that

  • consolidates per-interface counters into a unified, system-wide view

  • collects statistics from all line cards and aggregates them in the local statistics infrastructure, and

  • provides fast, tabular summaries of PFC and PFC watchdog behavior across all interfaces.

This feature enables you to quickly monitor overall PFC and watchdog activity without running per-interface commands. It improves troubleshooting speed and provides a holistic view of congestion control across the chassis.

Table 1. Feature History Table

Feature Name

Release Information

Feature Description

Global Statistics Counters for Priority Flow Control and Priority Flow Control Watchdog

Release 25.4.1

Introduced in this release on: Fixed Systems (8010 [ASIC: A100])(select variants only*)

*This feature is supported on:

  • 8011-32Y8L2H2FH

  • 8011-12G12X4Y-A/D

Global Statistics Counters for Priority Flow Control and Priority Flow Control Watchdog

Release 25.1.1

Introduced in this release on: Fixed Systems (8700 [ASIC: K100], 8010 [ASIC: A100])(select variants only*)

This feature is supported on:

  • 8712-MOD-M

  • 8011-4G24Y4H-I

Global Statistics Counters for Priority Flow Control and Priority Flow Control Watchdog

Release 24.4.1

Introduced in this release on: Fixed Systems (8200 [ASIC: P100], 8700 [ASIC: P100])(select variants only*); Modular Systems (8800 [LC ASIC: P100])(select variants only*)

*This feature is supported on:

  • 8212-48FH-M

  • 8711-32FH-M

  • 88-LC1-36EH

  • 88-LC1-12TH24FH-E

  • 88-LC1-52Y8H-EM

Global Statistics Counters for Priority Flow Control and Priority Flow Control Watchdog

Release 7.5.5

Release 24.2.11

You can now view statistics for Priority Flow Control (PFC) and PFC Watchdog for all interfaces in a consolidated, compact, tabular, and easy-to-read format.

We’ve also made the display of these global statistics faster by ensuring data is collected from all line cards for their interfaces and cumulatively sent to the local statistics infrastructure from where the show commands collect the data.

Previously, you could view statistics only per interface for PFC and PFC Watchdog, wherein the show commands get the data from each interface.

This feature modifies the following command:

View global statistics for Priority Flow Control and Priority Flow Control watchdog

Use this task to view the consolidated statistics for all interfaces on the router, enabling faster validation of Priority Flow Control (PFC) or PFC watchdog behavior.

Procedure

1.

View global PFC statistics.

Example:

Router#show controllers all priority-flow-control statistics location all
Interface               TC   RxPFC   TxPFC   RxDropped
FourHundredGigE0/0/0/0  0    0       0       NA
FourHundredGigE0/0/0/0  7    0       0       NA
FourHundredGigE0/0/0/0  all  0       0       0

This example displays traffic-class-based PFC statistics for all interfaces where:

  • Rx PFC displays the number of received PFC frames

  • Tx PFC displays the number of transmitted PFC frames

  • Rx Dropped displays the number of PFC frames dropped. 0 indicates that no frames were dropped, while NA indicates the information is not available because the line card has not sent the data.

2.

View global PFC watchdog statistics.

Example:

Router#show controllers all priority-flow-control watchdog-stats location all 
 
Interface                TC   Watchdog  Shutdown  Auto Restore SAR   SAR Instantaneous   Total Dropped  Dropped
                  Events      Events    Events    Events       Events      Events
FourHundredGigE0/0/0/0    0      0        0         0           0          0                0              0
FourHundredGigE0/0/0/0    7      0        0         0           0          0                0              0
FourHundredGigE0/0/0/1    0      0        0         0           0          0                0              0
FourHundredGigE0/0/0/1    7      0        0         0           0          0                0              0
FourHundredGigE0/0/0/2    0      0        0         0           0          0                0              0
FourHundredGigE0/0/0/2    7      0        0         0           0          0                0              0
FourHundredGigE0/0/0/3    0      0        0         0           0          0                0              0
FourHundredGigE0/0/0/3    7      0        0         0           0          0                0              0
FourHundredGigE0/0/0/4    0      0        0         0           0          0                0              0

This example displays statistics across all interfaces for watchdog activity for every traffic class, where:

  • Watchdog Events indicates how many times the watchdog module receives notifications that excess PFC frames have been received

  • Shutdown events displays the number of times the PFC watchdog moves the queue to the shutdown state

  • Auto restore Events displays the number of times the PFC watchdog sets the auto-restore timer

  • Total Dropped displays the cumulative virtual output queue (VOQ) drops and the output drops in all the watchdog events from the time you ran the clear controllers priority-flow-control watchdog statistics command to clear the statistics counter

  • Dropped indicates the cumulative VOQ drops and the output queue drops in the most recent watchdog shutdown event.

Disregard the SAR Events and SAR Instantaneous Events counters because they have no operational impact.

You can verify that PFC frames, pause activity, and watchdog operations are visible across all interfaces. This visibility helps confirm overall congestion health.

Supported commands for global statistics for Priority Flow Control and Priority Flow Control watchdog

Use these commands to display or clear global statistics for Priority Flow Control (PFC) and PFC watchdog.

Operation

Command

Description

View global PFC statistics

show controllers all priority-flow-control statistics location all

Displays consolidated PFC statistics, including pause frame counts and flow control events across all interfaces and NPUs.

View global PFC watchdog statistics

show controllers all priority-flow-control watchdog-stats location all

Displays cumulative PFC watchdog statistics, including watchdog events, shutdowns, and auto-restore counts for each traffic class.

Clear PFC statistics

clear controller priority-flow-control statistics

Clears all PFC global counters and resets the corresponding per-interface counters that the show controllers all priority-flow-control statistics location all command displays.

Clear PFC watchdog statistics

clear controller priority-flow-control watchdog-stats

Clears all PFC watchdog global counters and resets the per-interface watchdog statistics that the show controllers all priority-flow-control watchdog-stats location all command displays.

After running a clear command, all counter values reset to zero and begin incrementing again as new pause or watchdog events occur.