Optimize monitoring performance

[coldzerofear]

What type of PR is this?

What this PR does / why we need it:

Which issue(s) this PR fixes: Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 60 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
pkg/lister/pod.go	0.00%	32 Missing :warning:
pkg/monitor/nvidia/cudevshr.go	0.00%	28 Missing :warning:

Flag	Coverage Δ
unittests	27.19% <0.00%> (-0.32%)	:arrow_down:

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
pkg/monitor/nvidia/cudevshr.go	0.00% <0.00%> (ø)
pkg/lister/pod.go	0.00% <0.00%> (ø)

... and 2 files with indirect coverage changes