Single file IntelliSense consumes massive CPU indexing all system includes

[MichaelGrupp]

Hi guys,

I experience a high CPU load, apparently caused by the C++ extension. One core is always used 100% even when no files are being edited. The problem doesn't occur with code --disable-extensions. My issue looks similar to this one: microsoft/vscode#33176

Here's my configuration:

• VSCode Version: Code 1.17.0 (be377c0faf7574a59f84940f593a6849f12e4de7, 2017-10-04T23:33:45.303Z)
• OS Version: Linux x64 4.4.0-96-generic
• Extensions:

Extension	Author (truncated)	Version
gc-excelviewer	Gra	1.1.15
code-settings-sync	Sha	2.8.3
githistory	don	0.2.3
python	don	0.7.0
gitlens	eam	5.4.1
LogFileHighlighter	emi	1.2.0
terminal	for	0.0.10
vscode-auto-open-markdown-preview	hnw	0.0.4
cpptools	ms-	0.13.1
platformio-ide	pla	0.7.3
shebang-snippets	rpi	0.0.3
bash-beautify	sha	0.1.1
rst-vscode	tht	2.0.0
cmake	twx	0.0.17
cmake-tools	vec	0.10.2
gitblame	wad	2.2.0
debug	web	0.21.2

---

Steps to Reproduce:

1. open vscode with C++ extension
2. do nothing, the CPU load is always high

Reproduces without extensions: No

[MichaelGrupp]

[Irvel]

I'm experiencing the exact same issue in macOS.

• VSCode Version 1.17.0 (1.17.0) (be377c0faf7574a59f84940f593a6849f12e4de7, 2017-10-05T06:03:48.991Z)

• macOS 10.13

• Microsoft C/C++ for VSCode Version 0.13.1

[sean-mcmanus]

What are your c_cpp_properties.json settings? Depending on your browse settings, this might be "by design". You can enable logging to see if there's unexpected work occurring: https://github.com/Microsoft/vscode-cpptools/blob/master/Documentation/LanguageServer/Enabling%20logging.md .

[bobbrow]

An hour and a half of parsing seems too much, even for large projects. Can you give us more information about the project? How many files? Is it open source so we can try to debug the problem locally? As Sean mentions, the "browse.path" setting may have an impact because we will recursively scan folders, so try not to include the same subfolders multiple times until we add support to prune rescans.

[MichaelGrupp]

ahh, interesting hint. When I experienced this, I had no folder selected (just opened a single file for quick editing).

I just opened a random folder and the problem disappeared. It seems to re-appear when the folder is closed with ctrl + kf. As mentioned, this happens without opened files, too.

Here are some logs generated with the env. variables from the link of @sean-mcmanus posted above at loglevel 5.

• no folder selected on startup: vscode.cpp.log.6113_no_folder_opened.txt
• startup with a folder selected: vscode.cpp.log.6470_folder_preselected.txt

Looking at the logs it seems like the recursion runs amok when there's no folder selected? 🤔

[bobbrow]

Thank you for the logs. That was super helpful. It looks like VS Code is not sending us a root path when you open a single file and we end up treating all of the system includes as part of your "workspace" which means that we won't skip parsing them.

add folder to browse.path: /usr/include/c++/5.4.0
add folder to browse.path: /usr/include/x86_64-linux-gnu/c++/5.4.0
add folder to browse.path: /usr/local/include
add folder to browse.path: /usr/lib/clang/3.8.0/include
add folder to browse.path: /usr/include
add folder to browse.path: /usr/include/x86_64-linux-gnu
add folder to browse.path:      <--  empty path

[MichaelGrupp]

Glad to help, hope you get this fixed soon. The workaround until then is just to open a folder 😉

[bobbrow]

We released 0.14.0 with a fix for this. Please let us know if you continue to have issues.