CPU 800%

[mozhuanzuojing]

environment：

Version: 1.81.1 (system setup)
Commit: 6c3e3dba23e8fadc360aed75ce363ba185c49794
Date: 2023-08-09T22:22:42.175Z
Electron: 22.3.18
ElectronBuildId: 22689846
Chromium: 108.0.5359.215
Node.js: 16.17.1
V8: 10.8.168.25-electron.0
OS: Windows_NT x64 10.0.22621
vscode.java 1.21.0

issue

In normal use, the java plugin occupies a lot of CPU （800%）， It lasted half an hour
It feels related to the slow copy-paste, I now write code in two minutes and paste a line of code.

screen

java log

java log.zip

jfr 【2min】

flight_recording_1707Eclipse11788_1.zip

[rgrunber]

Thanks for the jfr file. It definitely helps.

Yes, if something like a paste action is taking a long time (I clearly saw certain delegate commands taking anywhere from 6s-60s) then clearly the language server is busy with some other computations. In regular usage, I only usually see that on project import. There can be a moment where the language server has signalled it's ready to accept requests, but is still busy with certain aspects of the project build. This definitely doesn't seem like that though, since the server is already up and handling requests for some time.

I noticed there were about 12 worker threads, all active at once. That might explain the slowness :

Pretty much all but one have a call stack that looks like this :

Seems like getIntroduceParameterProposals() from the refactoring proposals is taking a lot of time to compute. Particularly the type hierarchy creation part. Likely just clicking around causes this, as that triggers the code action request.

Is there something about the project that in the workspace that might be causing this ? Is this something new that didn't happen on previous versions ?

[mozhuanzuojing]

Likely just clicking around causes this, as that triggers the code action request.

In fact, I only did two copy-paste actions in VSCODE and waited for the JFR result until the end

[mozhuanzuojing]

Is this something new that didn't happen on previous versions ?

Yes. It has been running smoothly for three years (in my work) until the last two versions had this problem

[mozhuanzuojing]

Is there something about the project that in the workspace that might be causing this ?

I've been using the same project for two years, not quite like it's caused by the project

[mozhuanzuojing]

One night later (12 hours), this morning came and did only three copy-paste operations in VSCODE, followed by 3min recording of JFR. But the only difference is that copy-paste is now fast.

jfr 3min

flight_recording_1707Eclipse5255.zip

[rgrunber]

• I see in the original report you're using vscode-java 1.21.0. What's the earliest version of vscode-java you can reproduce this on ?
• Does anything improve if you set "java.jdt.ls.lombokSupport.enabled": false ?
• Are you able to share the project on which this issue occurs ? I have not been able to get any of the worker threads to spend as much time in the code action logic as I see spent in the recordings you've provided :\

Even your most recent jfr shows a bunch of worker threads spawned by the language server spending most of their time computing the type hierarchy for the Introduce Parameter... refactoring command. It shouldn't be taking that long.

CC'ing @snjeza in case there is something she may be aware of.

[snjeza]

I've been using the same project for two years, not quite like it's caused by the project

@mozhuanzuojing could you attach a project example?

[mozhuanzuojing]

• I see in the original report you're using vscode-java 1.21.0. What's the earliest version of vscode-java you can reproduce this on ?

There are no exact tests, but the version was lowered from my colleague's machine before, and at 1.18.0 it was no problem.

[mozhuanzuojing]

• Does anything improve if you set "java.jdt.ls.lombokSupport.enabled": false ?

Tested with this parameter today, and there is no change.

[mozhuanzuojing]

• Are you able to share the project on which this issue occurs ? I have not been able to get any of the worker threads to spend as much time in the code action logic as I see spent in the recordings you've provided :\

@mozhuanzuojing could you attach a project example?

---

I'm very sorry, the company's internal projects cannot be shared; and because the project (about 5000 java files) and dependent (about 3000 jars) are relatively large, I feel unable to make a sample project.

However, can you add some special logging in vscode.java, so that I can record some specific help information on this basis.

Additional Information:

• I am using WSL2 environment on windows;
• In fact, this problem occurs on all machines of my team;
• I guess the eclipse JDT Index is damaged, resulting in the need to recalculate the structure of the class.
  Or the copied and pasted content is not originally part of the index, causing the index to always fail to hit, and then it is always being calculated.
• Is it possible to provide a config that turns off the ability to copy-paste parsing imported packages, which I suspect is a bit of a performance issue;
• I have a little doubt that this problem is related to the sandbox promotion of vscode, but I have not closed the sandbox to verify;
• Future expectations, I hope that the virtual thread of JDK21 will help.

[snjeza]

I think this is an upstream Eclipse issue.
@mozhuanzuojing Could you try VS Code 1.22.1 ?
It uses Java LS master and jdt.core I20230702-0220

[mozhuanzuojing]

I think this is an upstream Eclipse issue. @mozhuanzuojing Could you try VS Code 1.22.1 ? It uses Java LS master and jdt.core I20230702-0220

After installing this package, and after copying and pasting in vscode, the change in CPU usage suddenly increased to 1100%, and then gradually decreased to 300%, lasting for more than 5 minutes. The number of stutters when copying and pasting has been reduced a lot.

[snjeza]

@mozhuanzuojing I can't reproduce this issue.
Could you compare v1.22.1 with v1.18.0?
Does that issue exist in VS Code 1.19.0 and 1.20.0?

[snjeza]

@mozhuanzuojing Could you try VS Code 1.22.2?
It uses ideas from redhat-developer/vscode-java#3199 (comment)

• Handle the paste event synchronously in the main thread
• Optimize the performance of the code actions

[mozhuanzuojing]

@mozhuanzuojing Could you try VS Code 1.22.2? It uses ideas from redhat-developer/vscode-java#3199 (comment)

• Handle the paste event synchronously in the main thread
• Optimize the performance of the code actions

Using this verison to test on two computers, copy-paste no longer stutters(<2s).
CPU usage averages 100% (one logical processor) for about 3 to 5 minutes before dropping to 0%.
In general, it is not slow if the CPU usage rate lower than 200%.

this is jfr 5min

flight_recording_1707Eclipse6879_2.zip