add readme with instruction on how to compare snapstart times

Author: ppittle

src/NET8MinimalAPISnapSnart/README.md

@@ -0,0 +1,74 @@
+# Comparing performance with SnapStart enabled or disabled
+
+1. Navigate to code directory
+```
+C:\projects\aws-samples\serverless-dotnet-demo\src\NET8MinimalAPISnapSnart>
+```
+
+2. Deploy this project using the SAM Cli:
+
+```
+sam build && sam deploy
+```
+
+3. SAM will output the root API Gateway endpoint URL:
+
+```
+---------------------------------------------------------------------------------------------------------------------
+Outputs
+---------------------------------------------------------------------------------------------------------------------
+Key                 ApiUrl
+Description         API Gateway endpoint URL
+Value               https://123example.execute-api.us-west-2.amazonaws.com/
+
+```
+4. Initialize Lambdas:
+```
+$baseUrl = "https://123example.execute-api.us-west-2.amazonaws.com/"
+
+Invoke-WebRequest $baseUrl/regular/test
+Invoke-WebRequest $baseUrl/snapstart/test
+
+Sleep -Seconds 1
+
+Invoke-WebRequest $baseUrl/regular/test
+Invoke-WebRequest $baseUrl/snapstart/test
+```
+
+5. Run Artillery
+
+```
+cd ..\..\loadtest\
+
+artillery run load-test.yml --target "$baseUrl/snapstart"
+
+artillery run load-test.yml --target "$baseUrl/regular"
+```
+
+6. Analyze the Results
+
+In the AWS Console, navigate to Cloud Watch Log Insights.
+
+Select the Log Groups for the `ApiWithSnapstart` and `ApiWithoutSnapstart` lambda functions.
+
+Run the following Query:
+
+```
+filter @type = "REPORT"
+  | parse @log /\d+:\/aws\/lambda\/(?<function>.*)/
+  | parse @message /Restore Duration: (?<restoreDuration>.*?) ms/
+  | stats
+count(*) as invocations,
+pct(coalesce(@initDuration,0)+coalesce(restoreDuration,0), 50) as p50,
+pct(coalesce(@initDuration,0)+coalesce(restoreDuration,0), 90) as p90,
+pct(coalesce(@initDuration,0)+coalesce(restoreDuration,0), 99) as p99,
+pct(coalesce(@initDuration,0)+coalesce(restoreDuration,0), 99.9) as p99.9,
+pct(@duration, 50) as durP50,
+pct(@duration, 90) as durP90,
+pct(@duration, 99) as durP99,
+pct(@duration, 99.9) as durP99.9
+group by function, ispresent(restoreDuration) as restore, (ispresent(@initDuration) or ispresent(restoreDuration)) as coldstart
+  | sort by coldstart desc
+```
+
+The results table will show the difference in Duration and Initialization for coldstarts when Snapstart is disabled or enabled.  It also shows warm start time for reference.