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cpptools-srv2 taking up lots of time. #14693
Description
Environment
- OS and Version: macOS Tahoe 26.6.1
- VS Code Version: 1.133.0
- C/C++ Extension Version: Microsoft C/C++ DevTools
- If using SSH remote, specify OS of remote machine:
Bug Summary and Steps to Reproduce
Bug Summary: C++DevTools in vscode seems to use cpptools-srv2 to parse the C++ files? This is already enough to almost hang my machine - has only 16Gb. Would be nice to get some
- warning about what it will do
- limit on memory? Limit on number of parallel compilations?
Configuration and Logs
{
"configurations": [
{
"name": "Mac",
"includePath": [
"${workspaceFolder}/**"
],
"defines": [],
"compilerPath": "/usr/bin/clang",
"cStandard": "c17",
"cppStandard": "c++14",
"intelliSenseMode": "macos-clang-arm64"
}
],
"version": 4
}Other Extensions
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MarijnKoesen commentedon Aug 19, 2026
I have the same, it's blasting full CPU constantly since an update earlier today.
forrestjgq commentedon Aug 19, 2026
same issue, until I disabled cpp tools extention
Colengms commentedon Aug 19, 2026
The
cpptools-srv2process parses files into the browse database (which supports several features). That behavior has not changed, just moved into a dedicated process (formerly done in the main cpptools process directly). Making full use of the CPU to accomplish that work as quickly as possible, is by-design.You might try increasing the log level (
"C_Cpp.loggingLevel": "Debug"), and monitoring the output, in case you're encountering an issue, such as parsing of files that shouldn't be parsed, following symlinks outside of your project folder, or perhaps repeatedly failing to parse the same file(s). If you're opening a huge repo (or root of an HD), you may want to isolate what is parsed using thebrowse.pathfield in ac_cpp_properties.jsonfile, or theC_Cpp.default.browse.pathsetting.forrestjgq commentedon Aug 20, 2026
Problem is:
My project is written by Python, it does NOT contain any c/cpp file, as well as CMakeList.txt, after updating to latest vsc, the cpp-tools just consumes too much CPU resource, what does it do? there is no reason I can think of.
sean-mcmanus commentedon Aug 20, 2026
江国庆/Forrest (@forrestjgq) We have a potential fix pending for 1.34.0 -- 1.33.8 can try to parse extensionless files when it shouldn't. If you check your logging and see "Parsed file" logging that is most likely the cause.
ItsThareesh commentedon Aug 25, 2026
My CPU usage is horrible.
sean-mcmanus commentedon Aug 26, 2026
mattijsjanssens Marijn Koesen (@MarijnKoesen) 江国庆/Forrest (@forrestjgq) Thareesh Prabakaran (@ItsThareesh) We have some fixes in https://github.com/microsoft/vscode-cpptools/releases/tag/v1.34.0 (pre-release). However, depending on what exactly you're hitting, there might still be an "issue". We switched having multiple cpptools-srv2 processes due tag parsing to reduce the wall clock time (matches what VS 2026 does).
MarijnKoesen commentedon Aug 27, 2026
Thx Sean McManus (@sean-mcmanus) , it seems to be in a much better place now. I had uninstalled the plugin because it made my laptop/VSCode unuseable, so I installed 1.34 today.
It started of with a few processes, which I guess is expected, but not as crazy as it used to be:
Now a few minutes later it's settled down to 50% cpu on one core.
It's still a bit weird, because if I check the open files, there aren't any open files (related to my project), yet it constantly still uses between 0.5 and 1 core:
Maybe it's always been like this, I don't know, but at least my laptop is not trying to fly away anymore with all fans on max speed, like it was on 1.33 👍
sean-mcmanus commentedon Aug 27, 2026
Marijn Koesen (@MarijnKoesen) cpptools shouldn't be constantly using 1 core -- it's possible that it could be responding to something like file watchers. If you set C_Cpp.loggingLeve to the hidden value of "7" you may be able to see logging that shows what is causing the CPU usage and/or you could attach a debugger...however, I believe on mac the debugger attach is disabled due to some mac security feature but there might be some other way to get a perf trace with a call stack: https://github.com/microsoft/vscode-cpptools/wiki/Troubleshooting-Performance-Issues
MarijnKoesen commentedon Sep 1, 2026
Yes, something still isn't right, I've removed the plugin again, you can see halfway the graph when I uninstalled it, I wasn't even working on the project that has cpp code.
Anywhere, here are a few traces I did:
MarijnKoesen commentedon Sep 1, 2026
That's on v1.34.2 btw
BuriKizilkaya commentedon Sep 3, 2026
Update? I mean my WSL always crash because of this extension.
erwango commentedon Sep 7, 2026
I'm seeing nearly the same on Ubuntu v24.04.
CPPTools takes up to 80% of CPU while I don't have even one single C file opened in VSCode.
VsCode 1.122.1-178
sean-mcmanus commentedon Sep 9, 2026
Marijn Koesen (@MarijnKoesen) Oh, sorry -- I didn't notice your perf log screenshots. We released 1.34.4 with a bunch of fixes, but it sounds like you may still be hitting an issue we don't know about yet. I'll look into that....
sean-mcmanus commentedon Sep 9, 2026
Marijn Koesen (@MarijnKoesen) Your screenshots are with cpptools and not cpptools-srv2 so I created a new issue at #14757 .
sean-mcmanus commentedon Sep 9, 2026
So I'm closing this issue, but if someone still has an issue with cpptools-srv2, can they file an issue with more repro info?
sean-mcmanus commentedon Sep 14, 2026
Marijn Koesen (@MarijnKoesen) We fixed the issue with cpptools shown in your screenshots with https://github.com/microsoft/vscode-cpptools/releases/tag/v1.35.1 -- let us know more info if you or anyone else still hits an issue.
MarijnKoesen commentedon Sep 15, 2026
Thanks Sean, i've updated to 1.35.1, and so far (5 minutes) I don't see any excessive CPU usage anymore.
So looks like it's fixed. If I see it coming back i'll report back.
Thx for the fix!