I have an ASP.NET Core 5 web application that provides functionality that involves file upload + rather large processing (memory consumption mainly). After each processing (with success or not) the memory could be reclaimed.

I have a stress test the endpoint with large files and checked the w3wp.exe process Memory (it runs in IIS) which goes something like this:

• step 1: 400M
• step 2: 800M
• step 3: 1200M
• step 4: 1800M
• step 5: 1300M

So there seems to be no memory leak, but GC kicks in very late. I would like for it to begin the cleanup faster, but I cannot seem to find a way to do this. What I have found/tried:

• why the delay in collection? - objects larger than 85KB are considered large by the GC and will be collected less frequent than smaller objects
• forcing the GC collection after each operation - this can be done using GC.Collect(), but it is not recommended to do so
• Runtime configuration options for garbage collection - I have checked GC settings and applied a limit for System.GC.HeapHardLimit, the final configuration looking like this:

{
  "runtimeOptions": {
    "tfm": "net5.0",
    "framework": {
      "name": "Microsoft.AspNetCore.App",
      "version": "5.0.0"
    },
    "runtimeOptions": {
      "configProperties": {
        "System.GC.HeapHardLimit": 1000000000
      }
    },
    "configProperties": {
      "System.GC.Server": true,
      "System.Reflection.Metadata.MetadataUpdater.IsSupported": false,
      "System.Runtime.Serialization.EnableUnsafeBinaryFormatterSerialization": false
    }
  }
}

The memory still goes beyond 1GB and stays like this until I process more data and it is finally reclaimed.

• IIS application pool memory limit - setting the memory limit on the application pool will cause it to be recycled, not forcing the GC to act faster

The application runs on an internal shared server and I would like to have a reasonable peak memory for it.

posted over 2 years ago

CC BY-SA 4.0

2y ago

Alexei‭

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