Remove the need to allocate a Func on each compatibility cache lookup

[jebriede]

Bug

Fixes: NuGet/Home#10919

Regression? Last working version: N/A

Description

Instead of allocating a func to pass to the GetOrAdd method of the concurrent dictionary on each lookup, check the dictionary first to see if the entry already exists and evaluate its compatibility and add it to the cache only if it does not. That way, a Func does not need to be allocated for each lookup and reduces the overall GC pressure.

PR Checklist

• PR has a meaningful title

• PR has a linked issue.

• Described changes

• Tests

  • Automated tests added
  • OR
    Code is covered by existing tests
  • Test exception
  • OR
  • N/A

• Documentation

  • Documentation PR or issue filled
  • OR
  • N/A

[jebriede]

Using OrchardCore as the solution, this fix eliminates the following allocations:

Name                                                                      	Inc %	          Inc
 Type System.Func`2[NuGet.Frameworks.CompatibilityCacheKey,System.Boolean]	  0.6	   42,664,364
+ clr!?                                                                   	  0.6	   42,664,364
 + nuget.frameworks!CompatibilityProvider.IsCompatible                    	  0.6	   42,664,364

[nkolev92]

🔪 those allocations.

[erdembayar]

🚀

[aortiz-msft]

Could you please summarize the allocation impact of this fix for Solution Load in OrchardCore?

[jebriede]

Could you please summarize the allocation impact of this fix for Solution Load in OrchardCore?

@aortiz-msft: The allocations in this table quantify the impact this had when doing a restore for OrchardCore. Based on this profile, it's about 42MB of allocations that are no longer being made with this fix! 😄
#4095 (comment)

I plan on pulling data on the impact of each of my fixes on Solution Load with OrchardCore once this series of PRs have been merged.

[aortiz-msft]