I read that article before and just reread it now - thanks for writing it up, but I still have the same question I did the first time around. You posit:

> Because we run 200 invocations or so in parallel we’ll only need to download the model once and save it there

From my own reading of the Lambda docs, it seems that a simultaneous request for the same Lambda may or may not spin up a new container, ie while serial requests within the 15 minute timeout will likely reuse the same instance with the same frozen/cached tmp data, parallel requests do not have that assumption.

Was this your finding in practice? If so, were your CloudWatch “keep warm” events a series of just 1 Lambda invocation ~10/15min apart of 200 simultaneous requests serially spaced to keep the instances spun up?