scheduler: improve gang log

[googs1025]

Ⅰ. Describe what this PR does

I modified the current log level output method. In order to reduce log printing, I only print when --v=4 is used, and use klog.V().ErrorS for the err!=nil part.

Ⅱ. Does this pull request fix one issue?

fix: #1895 (comment)

Ⅲ. Describe how to verify it

Ⅳ. Special notes for reviews

V. Checklist

• I have written necessary docs and comments
• I have added necessary unit tests and integration tests
• All checks passed in make test

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.70%. Comparing base (e15a68c) to head (298ae4c).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2009   +/-   ##
=======================================
  Coverage   67.69%   67.70%           
=======================================
  Files         446      446           
  Lines       42686    42686           
=======================================
+ Hits        28898    28899    +1     
+ Misses      11269    11265    -4     
- Partials     2519     2522    +3     

Flag	Coverage Δ
unittests	67.70% <100.00%> (+<0.01%)	⬆️

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[googs1025]

@buptcozy @eahydra /PTAL

[hormes]

Why do we need to downgrade error logs to V4?

[googs1025]

Why do we need to downgrade error logs to V4?

Indeed, this level needs to be confirmed. However, setting the log level can effectively reduce the number of log prints.

[jasonliu747]

/assign @ZiMengSheng

[ZiMengSheng]

/lgtm

[googs1025]

Sorry for being late. I've been busy with other work recently. I'll go through the comments and make some revisions during the holidays.

[koordinator-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hormes

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[koordinator-bot]

New changes are detected. LGTM label has been removed.