Hey Kenton, great to see you chiming in here as well!
> Additionally, V8 is just much better at running JavaScript than you can hope to achieve in a Wasm-based JS implementation. And JavaScript is the most popular web development language (even server-side).
I agree with this statement as of today. Stay tuned because very cool things are coming on Wasm land (Spidermonkey will soon support JITted workloads inside of Wasm, bringing the speed much closer to V8!)
> Note that the time to initialize an isolate isn't actually on the critical path to cold start, since we can pre-initialize isolates and have them ready to go before knowing what application they will run
That's a good point. Although, you are kind of optimizing now the critical path to cold start by actually knowing what the app is running (if is Python, restore it from a Snapshot). So even though if isolate initialization is not in the critical path, there are other things on the critical path that amounts for the extra second of latency in cold starts for Python, I would assume.
> Minimizing application size is really essential to making edge compute inexpensive
By leveraging on proper-defined dependencies, you just need to compile and load in memory the dependency module once (lets say Python) and have "infinite" capacity for initializing them. Basically, if you put Python out of the picture and consider it a dependency of an app, then you can suddenly scale apps as much as you want there!
For example: having 10 Python versions (running thousands of apps) will have a overhead of 5Mb (Python binary size in avg) * 10 versions (plus a custom memory for each initialization of the app, which is required in either strategy) ~= 50Mb, so the overhead of pinning a specific Python version should be truly minimal on the server (at least when fully leveraging on a Wasm runtime)
> Additionally, V8 is just much better at running JavaScript than you can hope to achieve in a Wasm-based JS implementation. And JavaScript is the most popular web development language (even server-side).
I agree with this statement as of today. Stay tuned because very cool things are coming on Wasm land (Spidermonkey will soon support JITted workloads inside of Wasm, bringing the speed much closer to V8!)
> Note that the time to initialize an isolate isn't actually on the critical path to cold start, since we can pre-initialize isolates and have them ready to go before knowing what application they will run
That's a good point. Although, you are kind of optimizing now the critical path to cold start by actually knowing what the app is running (if is Python, restore it from a Snapshot). So even though if isolate initialization is not in the critical path, there are other things on the critical path that amounts for the extra second of latency in cold starts for Python, I would assume.
> Minimizing application size is really essential to making edge compute inexpensive
By leveraging on proper-defined dependencies, you just need to compile and load in memory the dependency module once (lets say Python) and have "infinite" capacity for initializing them. Basically, if you put Python out of the picture and consider it a dependency of an app, then you can suddenly scale apps as much as you want there!
For example: having 10 Python versions (running thousands of apps) will have a overhead of 5Mb (Python binary size in avg) * 10 versions (plus a custom memory for each initialization of the app, which is required in either strategy) ~= 50Mb, so the overhead of pinning a specific Python version should be truly minimal on the server (at least when fully leveraging on a Wasm runtime)