samuelcolvin / cloudflare-worker-speed-test

CloudFlare worker speed test

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Update: after changes to how cloudflare compiles WebAssembly described here the performance of CloudFlare workers with large wasm modules has improved enormously.

For the largest case below the response time has dropped from 2844ms to 211ms.

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See https://community.cloudflare.com/t/cloudflare-workers-very-slow-with-moderate-sized-webassembly-bindings/184668/12

This worker does one very simple thing: it substitutes the variable {{ name }} in a string and returns that string.

By default the template is Hello, {{ name }} and the value of name is world, both template and name can be customised using GET parameters.

The substitution can be done in the the following ways:

• in javascript using replace
• in rust use string replace
• in rust using regex replace_all
• in rust using tera one_off

Using these means of substitution varies the wasm module from non existent, to small, medium and large.

Performance results

mode	wasm size (kb)	mean response time (ms)	response stdev (ms)
javascript	0	84	8
simple replace, wee_alloc	20	127	26
simple replace, no wee_alloc	25	133	30
regex, wee_alloc, default-features off	193	540	235
regex, wee_alloc	619	1228	188
tera, wee_alloc, default-features off	1160	2744	452
tera, wee_alloc	2546	2844	496

Results are calculated using test_performance.py script above, the worker is modified by switching features in Cargo.toml, for the "javascript" case, mode has to be changed in wrangler.toml and some line commented and uncommented in worker/worker.js.