SERVERLESS PERFORMANCE LESSONS WITH HEADLESS CHOME @smithclay ServerlessConf NY, Oct 2017

SERVERLESS PERF STRATEGY ƛ ƛ is it fast? ƛ ƛ is it fast concurrently? ƛ ƛ what's the worst case? why?

AWS Lambda Function index.handler (node.js runtime) ./bin/chromedriver process.exec https://medium.com/clog/running-selenium-and-headless-chrome-on-aws-lambda-fb350458e4df ./bin/headless_chrome BIG BROWSER, LITTLE FUNCTION + Simple Selenium Script

AWS LAMBDA: BATTERIES INCLUDED DATA SOURCES Amazon Cloudwatch Logs Amazon Cloudwatch Metrics AWS X-Ray Traces

DISTRIBUTED TRACE VISUALIZTION 1200ms 400ms 370ms Service A Service B Service C Time

HELLO, COLD START AWS X-Ray Trace: AWS Function invoked from the Developer Console

COLD VS WARM START Notice: Function gets called almost immediately after the service receives the trigger.

COLD STARTS: MORE ANALYSIS NEEDED Aggregate function latencies from X-Ray to understand trends

VISUALIATING TRACES IN AGGREGATE 1) How long does it take for my function to initialize? 2) Where is time generally being spent?

FOR THIS FUNCTION, COLD STARTS ARE RARE Over a 24 hour period, the function rarely experiences cold starts.

AWS LAMBDA: COMMON SETTINGS TO MODIFY Language Runtime "Memory" Dropdown Function size (mb)

DURATION: BEFORE AND AFTER INCREASING MEMORY 768mb 1152mb Chromium needed more memory!

WRAP UP • Collect data for several days for many function runs. • Consider enabling x-ray traces for non-trivial functions • Test scenarios where your function has many concurrent executions (i.e. large spike in the number of requests) • Don't be afraid to increase memory: it might end up costing less. •Measure and share!

THANKS! slides: @smithclay + speakerdeck.com Original blog post: https://blog.newrelic.com/2017/06/20/lambda- functions-xray-traces-custom-serverless-metrics/