Flexible counter bank allocation

SR Linux devices allow flexible counter bank allocation for the following applications:

7250 IXR Gen 2c+

• Early Congestion Notification (ECN) statistics
• LSP statistics (ingress and egress)
• IP-in-IP tunnel statistics

7250 IXR Gen 3

• Early Congestion Notification (ECN) statistics
• IP-in-IP tunnel statistics

Some counter banks are pre-assigned for essential applications, for example, CPM filter counters, interface queue statistics, and so on. These pre-assigned banks cannot be modified. Other banks are free and available for assignment to the applications listed above. The number of banks you assign, along with their size, determines how many statistics can be collected. To view the list of banks you can allocate to an application, use the info from state with-context platform linecard forwarding-complex counter-banks command. See Displaying bank allocations on line cards for more information.

For each SR Linux device, you can select one of the supported applications and assign one or more free counter banks identified by unique IDs. Banks come in different sizes depending on the SR Linux device. You must match the application’s scale requirement to a bank large enough to store all counters. If a single bank is not large enough, you can allocate multiple banks to expand capacity. For example, assigning bank-id 1 to ingress-lsp-statistics, stores LSP ingress statistics in bank 1 on a specific device. Adding bank-id 4 to the same application expands the allocation, therefore increasing the capacity. See Performing counter bank allocations for more inforation. In addition to bank allocation, the applications may also have specific bank size or scaling requirements.

Counter banks available on 7250 IXR Gen 2c+

The following table lists the free counter banks with IDs and sizes available for allocation when a 7250 IXR Gen 2c+ device boots.

Table 1. Free counter banks available on 7250 IXR Gen 2c+

Bank ID	Bank size
1, 4	4K
13, 15	8K
19, 28, 29, 30, 31, 32, 33, 34	16K

Counter banks available on 7250 IXR Gen 3

The following table lists the free counter bank with IDs and sizes available for allocation when a 7250 IXR Gen 3 device boots.

Table 2. Free counter banks available for allocation on 7250 IXR Gen 3

Bank ID	Bank size
1, 2, 4, 11, 12	6K
21, 22, 23, 24	12K
30, 31	24K

Reboot requirements

Reboot requirements for flexible counter bank allocation are as follows:

• Reboot is not required for the following tasks:

  • Allocating a free bank to an application.
  • Adding a free bank to an existing application.
• Reboot is required for the following tasks:

  • An application evacuating a bank.
  • Replacing a bank with another bank, smaller or larger

The show command, info from state with-context platform resource-management counter-banks displays the pending allocations that require system reboot. See Verifying reboot status of bank allocations for more information.

Bank allocation considerations

The following considerations apply while allocating counter banks:

• If no bank is allocated or allocation fails and the application enables statistics, the node returns statistics as all zeros. The node reports the allocation failure back to the application. The node does not manage retries or maintain retry queues. The application retries using a bank when it becomes available.
• If counter banks are not available for additional entries, the node reports the shortage.
• Applications define their own maximum limits. Even if banks are available, statistics collection stops after the application reaches the maximum limit.

--{ + candidate shared default }--[  ]--
# info with-context platform resource-management counter-banks
    platform {
        resource-management {
            counter-banks {
                forwarding-complex-type Gen2c+ {
                    application egress-lsp-stats {
                        bank-allocation 1 {
                        }
                    }
                }
            }
        }
    }

--{ + candidate shared default }--[  ]--
# info from state with-context platform linecard 1 forwarding-complex 1 counter-banks
    platform {
        linecard 1 {
            forwarding-complex 1 {
                counter-banks {
                    bank 1 {
                        bank-size 4K
                        application ingress-lsp-stats {
                            entries 4096
                        }
                    }
                    bank 4 {
                        bank-size 4K
                        application ingress-lsp-stats {
                            entries 4096
                        }
                    }
                    bank 13 {
                        bank-size 8K
                        application unallocated {
                        }
                    }
                    bank 15 {
                        bank-size 8K
                        application unallocated {
                        }
                    }
                    bank 19 {
                        bank-size 16K
                        application unallocated {
                        }
                    }
                    bank 28 {
                        bank-size 16K
                        application unallocated {
                        }
                    }
                    bank 29 {
                        bank-size 16K
                        application unallocated {
                        }
                    }
                    bank 30 {
                        bank-size 16K
                        application unallocated {
                        }
                    }
                    bank 31 {
                        bank-size 16K
                        application unallocated {
                        }
                    }
                    bank 32 {
                        bank-size 16K
                        application unallocated {
                        }
                    }
                    bank 33 {
                        bank-size 16K
                        application unallocated {
                        }
                    }
                    bank 34 {
                        bank-size 16K
                        application unallocated {
                        }
                    }
                }
            }
        }
    }

--{ + candidate shared default }--[  ]--
# info from state with-context platform resource-management counter-banks
    platform {
        resource-management {
            counter-banks {
                chassis-reboot-required false
                forwarding-complex-type Gen2c+ {
                    application ingress-lsp-stats {
                        bank-allocation 1 {
                        }
                        bank-allocation 4 {
                        }
                    }
                }
            }
        }
    }

--{ + candidate shared default }--[  ]--
# info from state with-context platform resource-management counter-banks
    platform {
        resource-management {
            counter-banks {
                chassis-reboot-required true
                forwarding-complex-type Gen2c+ {
                    application ingress-lsp-stats {
                    }
                    application ip-in-ip-tunnel-stats {
                        bank-allocation 1 {
                        }
                        bank-allocation 4 {
                        }
                    }
                }
            }
        }
    }