[YUNIKORN-1881] Improve the performance of tryPlaceholderAllocate

[pbacsko]

What is this PR for?

tryPlaceholderAllocate() is too expensive. It copies and sorts apps and tries to find schedulable tasks even if we do not have placeholders at all. Applications should track if they have an active placeholder allocation to avoid unnecessary copy/sorting.

What type of PR is it?

• - Bug Fix
• - Improvement
• - Feature
• - Documentation
• - Hot Fix
• - Refactoring

Todos

• - Task

What is the Jira issue?

https://issues.apache.org/jira/browse/YUNIKORN-1881

How should this be tested?

Screenshots (if appropriate)

Questions:

• - The licenses files need update.
• - There is breaking changes for older versions.
• - It needs documentation.

[codecov]

Codecov Report

Merging #597 (1ab62ad) into master (068198a) will increase coverage by 0.05%.
Report is 1 commits behind head on master.
The diff coverage is 90.00%.

@@            Coverage Diff             @@
##           master     #597      +/-   ##
==========================================
+ Coverage   77.49%   77.55%   +0.05%     
==========================================
  Files          77       77              
  Lines       12586    12687     +101     
==========================================
+ Hits         9754     9839      +85     
- Misses       2518     2533      +15     
- Partials      314      315       +1     

Files Changed	Coverage Δ
pkg/scheduler/objects/queue.go	77.22% <85.71%> (+0.15%)	⬆️
pkg/scheduler/objects/application.go	68.17% <100.00%> (+0.13%)	⬆️

... and 6 files with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[craigcondit]

Looks ok I think. Would like @wilfred-s to take a look as well. +1.

[manirajv06]

Few more observations, but not exactly specific to this pr.

1. Some checks are repeated in mutiple try...() methods in queue. For example, app.IsAccepted() and sq.canRunApp()
2. Some checks can be carried out much more earlier in queue itself instead of doing in application. For example, queue and user headroom checks.

I think these checks can be kept in one single place.

Obsolete review

[wilfred-s]

LGTM