WASI VS .NET Runtime

WASI Co-chair here. Nothing in WASI is "somehow blocked by Google", or indeed blocked by anyone at all. Graphics support in WASI hasn't been developed simply because nobody has put energy into developing graphics support in WASI.

At the end of 2023 we counted around 40 contributors who have been working on WASI specifications and implementations: https://github.com/WebAssembly/meetings/blob/main/wasi/2023/... . That is a great growth for our project from a few years ago when that issue was filed, but as you can see from what people are working on, its all much more foundational pieces than a graphics interface. Also, if you look at who is employing those contributors, its largely vendors who are interested in WASI in the context of serverless. That doesn't mean WASI is limited to only serverless, but that has been the focus from contributors so far.

By rolling out WASI on top of the WASM Component Model we have built a sound foundation for creating WASI proposals that support more problem domains, such as embedded systems (@mc_woods and his colleagues are helping with this), or graphics if someone is interested in putting in the work. Our guide to how to create proposals is found here: https://github.com/WebAssembly/WASI/blob/main/Contributing.m... .

> As I understand it, it's not even really possible today to make WebAssembly do anything meaningful in the browser without trampolining back out to JavaScript anyway, which seems like a remarkable missed opportunity.

That's the underlying messy API it's built on. There are specs to make the API more standardized like https://github.com/WebAssembly/WASI

But overall, yeah, it feels like a shiny new toy everyone is excited about and wants to use. Some toys can be fun to play with, but it doesn't mean we have to rewrite production systems in it. Sometimes, or most of the time, toys don't become useful tools.

Snapshot Preview 1 is the standard all tools are building to right now. The specification is available here: https://github.com/WebAssembly/WASI/blob/main/legacy/preview...

It's pretty unreadable though!

Preview 2 looks like it will be a big change, and is just being finalised at the moment. I'd expect that when preview 2 is available there will be an improvement in the quality of documentation. I'm not sure how long it will take after release for tools to start switching to it. I'd expect Preview 1 will still be the main target at least for the rest of this year.

> Like WTF does this mean? The repo tells me nothing

Directly above the sentence you quoted:

"Interposition in the context of WASI interfaces is the ability for a Webassembly instance to implement a given WASI interface, and for a consumer WebAssembly instance to be able to use this implementation transparently. This can be used to adapt or attenuate the functionality of a WASI API without changing the code using it."

> and I've still yet to see a clear write-up about what WASI is.

In the same document: [0]

> WTF is wit?

The first link in that document ("Starting in Preview2, WASI APIs are defined using the Wit IDL.") is [1].

> I click on "legacy" and I see preview0 and preview1, which are basically unreadable proto-specs.

The README for the legacy directory [2] clearly explains what they are.

> Where's a single well-written WASI spec?

"Development of each API happens in its own repo, which you can access from the proposals list." [3]

> Whatever WASI is doing, I don't like it.

Clearly not - you've gone out of your way to ignore all of the documentation that answers your questions.

> And neither does AssemblyScript team apparently

The AssemblyScript team have a bone to pick with WASI based on their misunderstanding of what WASI is for (it is not intended for use on the web) and WASI's disinterest in supporting UTF-16 strings. You can see for yourself in [4].

[0]: https://github.com/WebAssembly/WASI/tree/main#wasi-high-leve...

The Bytecode Alliance initiated a sub-project called the WebAssembly System Interface (WASI). WASI is an API that allows WebAssembly access to system features such as files, filesystems, Berkeley sockets, clocks, and random numbers. WASI acts as a system-level interface for WebAssembly, so incorporating a runtime into a host environment and building a platform is easier.

We are excited to contribute back to Wasmtime and the component model, as well as to new projects and proposals emerging in this space (such as new Wasm proposals, like WASI Preview 2, wasi-keyvalue, wasi-sql or wasi-cloud).

I've been reading the following repositories.

https://github.com/WebAssembly/WASI/blob/main/Proposals.md

It's an interesting "time is a circle" problem given that a century only has 100 years and then we loop around again. 2-digit years is convenient for people in many situations but they are very lossy, and horrible for machines.

It reminds me of this breaking change to .Net from last year.[1][2] Maybe AA just needs to update .Net which would pad them out until the 2050's when someone born in the 1950s would be having...exactly the same problem in the article. (It is configurable now so you could just keep pushing it each decade, until it wraps again).

Or they could use 4-digit years.

[1] https://github.com/dotnet/runtime/issues/75148

These can also be passed as arguments to `dotnet publish` if necessary.

Reference:

- https://learn.microsoft.com/en-us/dotnet/core/deploying/nati...

- https://github.com/dotnet/runtime/blob/main/src/coreclr/nati...

- https://github.com/dotnet/runtime/blob/5b4e770daa190ce69f402... (full list of recognized keys for IlcInstructionSet)

Yes, that is true. I'm not sure about JVM implementation details but the reason the comment says "virtual and interface" calls is to outline the difference. Virtual calls in .NET are sufficiently close[0] to virtual calls in C++. Interface calls, however, are coded differently[1].

Also you are correct - virtual calls are not terribly expensive, but they encroach on ever limited* CPU resources like indirect jump and load predictors and, as noted in parent comments, block inlining, which is highly undesirable for small and frequently called methods, particularly when they are in a loop.

* through great effort of our industry to take back whatever performance wins each generation brings with even more abstractions that fail to improve our productivity

[0] https://github.com/dotnet/coreclr/blob/4895a06c/src/vm/amd64...

[1] https://github.com/dotnet/runtime/blob/main/docs/design/core... (mind you, the text was initially written 18 ago, wow)

If you care about portable SIMD and performance, you may want to save yourself trouble and skip to C# instead, it also has an extensive guide to using it: https://github.com/dotnet/runtime/blob/69110bfdcf5590db1d32c...

CoreLib and many new libraries are using it heavily to match performance of manually intensified C++ code.

DEBUG: packageFiles with updates (repository=local) "config": { "nuget": [ { "deps": [ { "datasource": "nuget", "depType": "nuget", "depName": "Microsoft.Extensions.Hosting", "currentValue": "7.0.0", "updates": [ { "bucket": "non-major", "newVersion": "7.0.1", "newValue": "7.0.1", "releaseTimestamp": "2023-02-14T13:21:52.713Z", "newMajor": 7, "newMinor": 0, "updateType": "patch", "branchName": "renovate/dotnet-monorepo" }, { "bucket": "major", "newVersion": "8.0.0", "newValue": "8.0.0", "releaseTimestamp": "2023-11-14T13:23:17.653Z", "newMajor": 8, "newMinor": 0, "updateType": "major", "branchName": "renovate/major-dotnet-monorepo" } ], "packageName": "Microsoft.Extensions.Hosting", "versioning": "nuget", "warnings": [], "sourceUrl": "https://github.com/dotnet/runtime", "registryUrl": "https://api.nuget.org/v3/index.json", "homepage": "https://dot.net/", "currentVersion": "7.0.0", "isSingleVersion": true, "fixedVersion": "7.0.0" } ], "packageFile": "RenovateDemo.csproj" } ] }

https://github.com/dotnet/runtime/issues/59591

Support zstd Content-Encoding:

We might not be that far away already. There is this issue[1] on Github, where Microsoft and the community discuss some significant changes.

There is still a lot of questions unanswered, but initial tests look promising.

Ref: https://github.com/dotnet/runtime/issues/94620

https://github.com/dotnet/dotnet exists for source build that stitches together SDK, Roslyn, runtime and other dependencies. A lot of them can be built and used individually, which is what contributors usually do. For example, you can clone and build https://github.com/dotnet/runtime and use the produced artifacts to execute .NET assemblies or build .NET binaries.

Yeah, it kind of is. There are quite a few of experiments that are conducted to see if they show promise in the prototype form and then are taken further for proper integration if they do.

Unfortunately, object stack allocation was not one of them even though DOTNET_JitObjectStackAllocation configuration knob exists today, enabling it makes zero impact as it almost never kicks in. By the end of the experiment[0], it was concluded that before investing effort in this kind of feature becomes profitable given how a lot of C# code is written, there are many other lower hanging fruits.

To contrast this, in continuation to green threads experiment, a runtime handled tasks experiment[1] which moves async state machine handling from IL emitted by Roslyn to special-cased methods and then handling purely in runtime code has been a massive success and is now being worked on to be integrated in one of the future version of .NET (hopefully 10?)

[0] https://github.com/dotnet/runtime/issues/11192

[1] https://github.com/dotnet/runtimelab/blob/feature/async2-exp...