Fix the issue Iluvatar device scheduling policy binpack and spread are reversed

[qiangwei1983]

What type of PR is this?
/kind bug

What this PR does / why we need it:
Fix the issue Iluvatar device scheduling policy binpack and spread are reversed

Which issue(s) this PR fixes:
Fixes #1589

[hami-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: qiangwei1983
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[gemini-code-assist]

Summary of Changes

Hello @qiangwei1983, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request resolves a bug in the Iluvatar device scheduling mechanism where the binpack and spread policies were effectively reversed. The fix involves a targeted modification to the device iteration order within the Fit function, ensuring that devices are processed in the correct sequence to align with the intended scheduling behavior and resolve the reported functional discrepancy.

Highlights

• Iluvatar Device Scheduling Policy Fix: Corrected the logic for Iluvatar device scheduling policies by reversing the iteration order when fitting devices. This change addresses the issue where binpack and spread policies were inadvertently swapped, ensuring they now function as intended.

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[gemini-code-assist]

Code Review

This pull request addresses an issue where the Iluvatar device scheduling policies for binpack and spread were reversed. The fix involves reversing the loop iteration order in the Fit function, which is a correct approach to solve the described problem. However, the unit tests have not been updated to account for this change in behavior, which will cause them to fail. I have left a comment detailing the required changes in the test file.

[gemini-code-assist]

This change correctly reverses the iteration order to fix the scheduling policy issue. However, it appears the unit tests have not been updated to reflect this change.

Specifically, Test_Fit in pkg/device/iluvatar/device_test.go has a "fit success" test case that provides two identical devices, dev-0 and dev-1, and expects dev-0 to be selected. With this change, the loop will iterate in reverse, so dev-1 will be selected first, causing the test to fail.

Please update the test case to expect dev-1 to be selected to ensure the tests pass and correctly reflect the new behavior.

[archlitchi]

please update the unit_test to pass the CI

[Shouren]

@qiangwei1983 I think it it better to use slices.Backward for traversing in reverse order with descending indices

[codecov]

Codecov Report

❌ Patch coverage is 40.66852% with 1065 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...ce-plugin/nvidiadevice/nvinternal/plugin/server.go	16.01%	169 Missing and 4 partials ⚠️
...evice-plugin/nvidiadevice/nvinternal/rm/rm_mock.go	0.00%	130 Missing ⚠️
...vice-plugin/nvidiadevice/nvinternal/plugin/util.go	22.58%	93 Missing and 3 partials ⚠️
pkg/device/awsneuron/device.go	76.36%	61 Missing and 8 partials ⚠️
...g/device-plugin/nvidiadevice/nvinternal/cdi/cdi.go	0.00%	68 Missing ⚠️
...-plugin/nvidiadevice/nvinternal/plugin/register.go	0.00%	66 Missing ⚠️
...e-plugin/nvidiadevice/nvinternal/plugin/factory.go	0.00%	48 Missing ⚠️
pkg/device/ascend/device.go	74.19%	42 Missing and 6 partials ⚠️
...device-plugin/nvidiadevice/nvinternal/imex/imex.go	0.00%	35 Missing ⚠️
pkg/device/amd/device.go	75.86%	31 Missing and 4 partials ⚠️
... and 19 more

Flag	Coverage Δ
unittests	51.09% <40.66%> (-10.05%)	⬇️

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

Files with missing lines	Coverage Δ
...ice-plugin/nvidiadevice/nvinternal/info/version.go	0.00% <ø> (ø)
...device-plugin/nvidiadevice/nvinternal/rm/helper.go	100.00% <100.00%> (ø)
pkg/device/common/common.go	53.33% <ø> (ø)
pkg/device/devices.go	81.12% <ø> (+7.47%)	⬆️
pkg/device/enflame/config.go	100.00% <ø> (ø)
pkg/device/enflame/device.go	83.25% <ø> (+5.16%)	⬆️
pkg/device/enflame/gcu.go	90.35% <ø> (ø)
pkg/device/hygon/device.go	91.22% <ø> (-2.15%)	⬇️
pkg/device/iluvatar/device.go	59.29% <ø> (-26.94%)	⬇️
pkg/device/kunlun/config.go	0.00% <ø> (ø)
... and 60 more

... and 5 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[archlitchi]

@ouyangluwei163 do you recall why we iterate iluvatar device in forward order? please reply here if you do

[ouyangluwei163]

#933