Omnisharp-vscode: Extension causes high cpu load

[nbonacchi]

• Issue Type: Performance
• Extension Name: csharp
• Extension Version: 1.17.1
• OS Version: Linux x64 4.18.0-15-generic
• VSCode version: 1.31.0

ms-vscode.csharp-unresponsive.cpuprofile.txt

Find more details here: https://github.com/Microsoft/vscode/wiki/Explain:-extension-causes-high-cpu-load

[akshita31]

@nbonacchi Can you try upgrading to the latest mono version as suggested here and checking if the problem still persists.
Also, we have a beta release containing major improvements on the code load times. You can install it by following the instructions here. Please let us know if that helps.

[JesseTG]

I have this same issue with Mono 5.18.

[joshampton]

I'm also running into similar performance issues. I've installed mono 5.16 64-bit (no GTK#) from the Visual Studio channel here and ensured it's on my path. Here's the version output:

>mono --version
Mono JIT compiler version 5.16.0 (Visual Studio built mono)
Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
        TLS:           normal
        SIGSEGV:       normal
        Notification:  Thread + polling
        Architecture:  amd64
        Disabled:      none
        Misc:          softdebug
        Interpreter:   yes
        LLVM:          supported, not enabled.
        GC:            sgen (concurrent by default)

I've also set "omnisharp.useGlobalMono": true to force it to use that version of mono.

Per @akshita31's recommendation above I've also installed the 1.18.0-beta7 version of the csharp extension via these instructions.

Here's the relevant bits about my setup:

• Extension Name: csharp
• Extension Version: 1.18.0-beta7
• OS Version: Windows_NT x64 10.0.17134
• VSCode version: 1.31.0 (user setup)

Here's my omnisharp configuration from settings.json:

{
  "omnisharp.autoStart": true,
  "omnisharp.disableMSBuildDiagnosticWarning": false,
  "omnisharp.loggingLevel": "information",
  "omnisharp.maxFindSymbolsItems": 1000,
  "omnisharp.maxProjectResults": 250,
  "omnisharp.minFindSymbolsFilterLength": 0,
  "omnisharp.projectLoadTimeout": 180,
  "omnisharp.useEditorFormattingSettings": true,
  "omnisharp.useGlobalMono": "always",
  "omnisharp.waitForDebugger": false,
}

I've also included a CPU profile: joshampton.CPU-20190211T014534.305Z.cpuprofile.txt

[akshita31]

@jrieken I downloaded the profile above that @joshampton uploaded and 96% of the time is consumed by (program). As per https://stackoverflow.com/questions/3847954/what-is-program-in-chrome-debugger-s-profiler this is the program itself. Does that mean it is vscode that is consuming time here ?

[jrieken]

Hard to say, generally it should be understood as time is spend outside JS-land, eg inside native land. This can be garbage collection or IPC message overflow. If you zoom in a lot you that some calls are interleaved with something I suspect as omnisharp message handling. Would it be possible that the omnisharp server send a lot of data?

[akshita31]

@jrieken Yeah omnisharp pushes a lot of messages and that might be the reason for this. I will investigate further into this. Thanks!

[floyd-may]

Does anyone have any recommendations for a workaround? I've got both Windows and Mac users on my team that are experiencing issues.

[akshita31]

@floyd-may I suspect the slow down maybe because omnisharp is sending a lot of messages. Could you try setting "omnisharp.loggingLevel" : error and restart vscode. That way it will only log error messages and might be faster

[floyd-may]

After a couple hours (I set it to warning because I have issues with following instructions 🙃 ) it's behaving better. Seems to be a reasonable workaround. I'll report back if I have more issues.

[joshampton]

despite setting the logging level to error, I'm still running into the same symptoms. Curiously, I'm running into this on my mac at work. Curiously it looks like mono-sgen64 is eating a ton of CPU. It seems to be triggered by intellisense. If I just type and never hit ctrl+space it seems to be fine.

[michaelstaib]

despite setting the logging level to error, I'm still running into the same symptoms. Curiously, I'm running into this on my mac at work. Curiously it looks like mono-sgen64 is eating a ton of CPU. It seems to be triggered by intellisense. If I just type and never hit ctrl+space it seems to be fine.

I am having the same.

[turowicz]

I get the same with #3336

[rhyswat]

I got this horribly with recent versions of VS Code inc. 1.40.2 on Ubuntu 18.04

I installed mono globally and set VS Code's extension to always use it.

OmniSharp server started with Mono 6.4.0.
    Path: /home/xyz/.vscode/extensions/ms-vscode.csharp-1.21.8/.omnisharp/1.34.8/omnisharp/OmniSharp.exe

[michaelstaib]

@rhyswat did it fix things?

[rhyswat]

@michaelstaib yes, so far so good. I've only just done it, but VS Code is now useable again.

[michaelstaib]

@rhyswat thanks for your feedback. Will try it out. It is sometimes strange these CPU peaks come and go. I have some files that I cannot open in VSCode, or if I do then the mono exe goes wild. Really annoying. Will try out if that works.