[portstat] Add FEC FLR statistics support to port counters

[apoorv-arista]

Add support to view FEC FLR (Frame Loss Ratio) statistics in
port counter statistics.

This includes

• FEC_FLR - observed FLR
• FEC_FLR_PREDICTED - predicted FLR computed by linear regression.

can be verified by viewing fec-stats either by portstat -f or show interfaces counters fec-stats

Feature HLD : port_fec_flr.md

What I did

Added FEC FLR (Frame Loss Ratio) statistics support to port counters display, including both actual and predicted FLR values.

How I did it

Added format_fec_flr() function to format FLR values consistently
Extended header_fec_only to include FEC_FLR and FEC_FLR_PREDICTED columns
Updated RateStats namedtuple to include fec_flr and fec_flr_predicted fields
Modified port statistics collection to retrieve FLR values from CHASSIS_STATE_DB
Updated display formatting to show FLR columns in fec-stats output

How to verify it

Run show interfaces counters fec-stats command and verify the output includes the new FEC_FLR and FEC_FLR_PREDICTED columns with properly formatted values.

Previous command output (if the output of a command-line utility has changed)

admin@ctd615:~$ show interfaces counters fec-stats
      IFACE    STATE    FEC_CORR    FEC_UNCORR    FEC_SYMBOL_ERR    FEC_PRE_BER    FEC_POST_BER    FEC_PRE_BER_MAX
-----------  -------  ----------  ------------  ----------------  -------------  --------------    ---------------
 Ethernet0        U           0             0                 0        1.48e-20        0.00e+00           1.78e-16
 Ethernet8        U           0             0                 0        1.98e-19        0.00e+00           1.67e-14
Ethernet16        U           0             0                 0        1.77e-20        0.00e+00           1.37e-13

New command output (if the output of a command-line utility has changed)

admin@ctd615:~$ show interfaces counters fec-stats
      IFACE    STATE    FEC_CORR    FEC_UNCORR    FEC_SYMBOL_ERR    FEC_PRE_BER    FEC_POST_BER    FEC_PRE_BER_MAX    FLR(O)    FLR(P) (Accuracy)
-----------  -------  ----------  ------------  ----------------  -------------  --------------    ---------------  ---------  -------------------
 Ethernet0        U           0             0                 0        1.48e-20        0.00e+00           1.78e-16   4.31e-10       7.81e-10 (89%)
 Ethernet8        U           0             0                 0        1.98e-19        0.00e+00           1.67e-14          0       4.81e-10 (84%)
Ethernet16        U           0             0                 0        1.77e-20        0.00e+00           1.37e-13   1.24e-10       6.03e-09 (79%)

[mssonicbld]

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[mssonicbld]

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[prgeor]

@apoorv-arista please fix the build errors

Also, update the PR as per the HLD

Can you put the link to the HLD in the PR description?

[prgeor]

@apoorv-arista please resolve the conflict

[mssonicbld]

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[mssonicbld]

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[mssonicbld]

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[mssonicbld]

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[mssonicbld]

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[mssonicbld]

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[mssonicbld]

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[mssonicbld]

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[apoorv-arista]

@apoorv-arista please resolve the conflict

resolved

[apoorv-arista]

@apoorv-arista please fix the build errors

Also, update the PR as per the HLD

Can you put the link to the HLD in the PR description?

The PR and the code are now consistent with the HLD.

@prgeor
sonic-utilities : precommit check failure for a portstat_test :
Its complaining about longer lines for sample table outputs
i think it needs to be taken care of manually as portstat_test is full of tables with long headers

https://dev.azure.com/mssonic/build/_build/results?buildId=960638&view=logs&j=62de8655-c4cb-5e46-7bfb-2697b4e2330c&t=a237fce0-9f85-5976-c187-01b35aae12e2

tests/portstat_test.py:48:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:49:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:50:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:51:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:52:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:53:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:57:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:58:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:59:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:60:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:61:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:87:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:88:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:89:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:90:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:91:121: E501 line too long (143 > 120 characters)
tests/portstat_test.py:92:121: E501 line too long (143 > 120 characters)