High CPU and very laggy Zed when using version 1.0.4 on MacOS

[mikedavies-dev]

After auto-upgrading to version 1.0.4 on MacOS the CSharp language server (roslyn) and Zed becomes unresponsive using near 100% CPU.

Stopping the Roslyn language server clears the issue but of course stops LSP support for the open buffer.

I've rolled back to version 1.0.2 and it works fine again so I suspect that it is something to do with this change.

I'm not sure what info would be required to reproduce this. I can provide LSP server logs if required.

System:

• MacOS 26.2 (25C56)
• Roslyn roslyn-5.5.0-2.26103.6
• Extension version: 1.0.4
• Zed 0.224.6

[lucypero]

The issue still persists. This extension is now unusable.

[lucypero]

Reverting to 1.0.2 didn't solve the issue for me. Zed becomes extremely slow after 2 seconds of roslyn use.

[reflectronic]

Can you try installing the latest daily build of Roslyn

dotnet tool install --global roslyn-language-server --source https://pkgs.dev.azure.com/azure-public/vside/_packaging/vs-impl/nuget/v3/index.json --version 5.5.0-2.26119.1

and then adding this to your settings.json file:

"lsp": {
  "roslyn": {
    "binary": {
      "path": "roslyn-language-server",
      "arguments": ["--stdio", "--autoLoadProjects"],
    },
  },
},

Does this help at all?

[lucypero]

`

Can you try installing the latest daily build of Roslyn

dotnet tool install --global roslyn-language-server --source https://pkgs.dev.azure.com/azure-public/vside/_packaging/vs-impl/nuget/v3/index.json --version 5.5.0-2.26119.1

and then adding this to your settings.json file:

"lsp": {
"roslyn": {
"binary": {
"path": "roslyn-language-server",
"arguments": ["--stdio", "--autoLoadProjects"],
},
},
},

Does this help at all?

Tool 'roslyn-language-server' failed to update due to the following:
The settings file in the tool's NuGet package is invalid: Settings file 'DotnetToolSettings.xml' was not found in the package.
Tool 'roslyn-language-server' failed to install. Contact the tool author for assistance.

[reflectronic]

Do you have the .NET 10 SDK installed? It's required by Roslyn

[mikedavies-dev]

@reflectronic, thanks for the suggestions. I've done the following:

1. Installing the latest daily build of Roslyn

λ> dotnet tool install --global roslyn-language-server --source https://pkgs.dev.azure.com/azure-public/vside/_packaging/vs-impl/nuget/v3/index.json --version 5.5.0-2.26119.1
Skipping NuGet package signature verification.
Since you just installed the .NET SDK, you will need to reopen terminal before running the tool you installed.
You can invoke the tool using the following command: roslyn-language-server
Tool 'roslyn-language-server' (version '5.5.0-2.26119.1') was successfully installed.

Appears to have installed OK.

2. Add the changes to the settings.json

When restarting the Roslyn server I get the following error:
"roslyn-language-server" "--stdio" "--autoLoadProjects": No such file or directory (os error 2)

I've had a look in the Roslyn folder for the exact location but I don't seem to have a roslyn-language-server executable on my machine. I've been looking in /Users/<User>/Library/Application Support/Zed/extensions/work/csharp.

In the previous version (roslyn-5.4.0-2.26060.1) I have a csharp-language-server which works fine but in roslyn-5.5.0-2.26103.6 I don't have anything that looks like a language server:

The slow/lagging version appears to be loading something but I'm not sure what. I've tried to look at the LSP logs in the updated version but they don't appear for some reason, i.e. there is no options available to view the logs with 1.0.4 loaded.

I do notice there is a version mismatch between the installed Roslyn version mentioned in the tool install command that you send and the version installed by 1.0.4 in my Zed extensions folder, I'm not sure if that's relevant or not?

[reflectronic]

Can you do which roslyn-language-server and set that as the path?

[mikedavies-dev]

I can't find any instance of roslyn-language-server on my machine.

Update:

Found a few instances but none are in the path

λ> find / -name "roslyn-language-server" 2>/dev/null
/System/Volumes/Data/Users/<User>/.dotnet/tools/.store/roslyn-language-server
/System/Volumes/Data/Users/<User>/.dotnet/tools/.store/roslyn-language-server/5.5.0-2.26119.1/roslyn-language-server
/System/Volumes/Data/Users/<User>/.dotnet/tools/roslyn-language-server
/Users/<User>/.dotnet/tools/.store/roslyn-language-server
/Users/<User>/.dotnet/tools/.store/roslyn-language-server/5.5.0-2.26119.1/roslyn-language-server
/Users/<User>/.dotnet/tools/roslyn-language-server

[mikedavies-dev]

I set the path in settings to the executable at /Users/<User>/.dotnet/tools/roslyn-language-server and updated the extension to 1.0.4 again but still had the same slow performance.

The LSP server does appear to be working as I can see messages in the LSP server log but zed becomes unresponsive.

[lucypero]

Do you have the .NET 10 SDK installed? It's required by Roslyn

I had .NET 9

I now installed .Net 10 and the latest roslyn LSP and configured Zed to use it. That didn't solve the problem. Zed becomes extremely unresponsive after using the extension for 2 seconds. I tried previous versions and it's the same issue.

[kevin-mueller]

Are you sure it's laggy forever? For me its laggy during the startup phase of the lsp. Which takes ~1 Minute for a large solution (100+ projects) on my machine. After that, it's smooth again.

[reflectronic]

Thanks. I believe I've identified the issue: zed-industries/zed#49778

The fix will be available in v0.226.x. I'll leave this issue open so you can confirm whether the slowdown is solved.

[reflectronic]

Sorry, but we had to revert my attempted fix in v0.226 because it was causing other performance issues. I'll come up with something for v0.227.