System.Reflection.MetadataLoadContext performance

[jonathanpeppers]

I have a benchmark here: https://github.com/jonathanpeppers/Benchmarks/blob/7db49fb3d272c5b07deda166dd4f5a5112258bbe/Benchmarks/Cecil.cs#L90-L111

And I am getting "not so great" results for SR.MetadataLoadContext:

// * Summary *

BenchmarkDotNet=v0.11.3, OS=Windows 10.0.18362
Intel Core i9-9900K CPU 3.60GHz, 1 CPU, 16 logical and 8 physical cores
  [Host]     : .NET Framework 4.7.2 (CLR 4.0.30319.42000), 32bit LegacyJIT-v4.8.4010.0
  DefaultJob : .NET Framework 4.7.2 (CLR 4.0.30319.42000), 32bit LegacyJIT-v4.8.4010.0


                                Method |        Mean |      Error |     StdDev |      Median | Gen 0/1k Op | Gen 1/1k Op | Gen 2/1k Op | Allocated Memory/Op |
-------------------------------------- |------------:|-----------:|-----------:|------------:|------------:|------------:|------------:|--------------------:|
            System.Reflection.Metadata |    32.84 ms |  0.1200 ms |  0.1123 ms |    32.85 ms |   3000.0000 |     62.5000 |           - |            15.12 MB |
                            Mono.Cecil |   351.81 ms |  7.1738 ms | 21.1522 ms |   339.38 ms |  16000.0000 |  12000.0000 |   4000.0000 |           103.57 MB |
 System.Reflection.MetadataLoadContext | 2,058.91 ms | 19.9863 ms | 18.6952 ms | 2,051.50 ms |  97000.0000 |  90000.0000 |   6000.0000 |           544.84 MB |

The performance compared to using raw SRM or Mono.Cecil is drastically worse.

I expected it to be somewhere in the middle of using SRM and Mono.Cecil. Is there something I'm doing here that would explain the poor performance?

Thanks!

[steveharter]

Moving to future due to scheduling + priority.