Comment by laurencerowe | Hacker News Reader

Comment by laurencerowe | Hacker News Reader

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This is really exciting. The 2.5us snapshot restore performance is on a par with Wasmtime but with the huge advantage of being able to run native code, albeit with the disadvantage of much slower but still microsecond interop.

I see there is a QuickJS demo in the tinykvm_examples repo already but it'd be great to see if it's possible to get a JIT capable JavaScript runtime working as that will be an order of magnitude faster. From my experiments with server rendering a React app native QuickJS was about 12-20ms while v8 was 2-4ms after jit warmup.

I need to study this some more but I'd love to get to the point where there was a single Deno like executable that ran inside the sandbox and made all http requests through Varnish itself. A snapshot would be taken after importing the specified JS URl and then each request would run in an isolated snapshot.

Probably needs a mechanism to reset the random seed per request.

You can run v8 jitless, if you want. It's going to be much faster than QuickJS. Adding JIT support means adding a fixed executable range, which you also can do already, but you can't run it in the dumb CLI example. JITs love to be W+X. So, not sure if it's an afternoon amount of work yet, due to security implications.

I have experience with this from libriscv, where I also embed JIT run-times like v8 and LuaJIT already.

From my tests v8 jitless was about 50% faster than QuickJS but still almost an order of magnitude slower than with JIT.

Note that I mistranscribed the numbers above: QuickJS was 18-24ms while v8 without warmup was 12-20ms (which I think is similar to jitless perf) and warmed jit was 2-4ms when I benchmarked a couple of years back. https://news.ycombinator.com/item?id=33793181

Thanks for the complexity warning. Sounds like I need to wait for an embedded JIT example using fixed executable range before I start playing around. But it would be fun to try and make Deno run inside it somehow, perhaps building on deno_runtime and hooking the http client user agent to make requests through Varnish. Deno's permission system should allow cleanly disabling unavailable functionality like access to the file system.

I see some examples that seem to use glibc but I was under the impression only musl binaries can be truly static? Can binaries built against glibc be used with TinyKVM?

Yes, you can use glibc with -static!

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