IntelliSense Updating and Parsing Workspace speed is much slower after 1.18.5

[LittleFatHero]

Environment

• OS and Version: windows 10
• VS Code Version: 1.89.0
• C/C++ Extension Version: 1.20.5
• If using SSH remote, specify OS of remote machine: ubuntu 20.04

Bug Summary and Steps to Reproduce

Bug Summary:
My vscode is running in windows 10 and I connected to remote machine ubuntu 20.04 which has installed vscode server and cpptools using the ssh remote-SSH extensions. when I open a C source file and go to definition of a function， it could not jump to the definition because cpptools is Updating IntelliSense and Parsing Workspace. So I wait for cpptools to finish the job, but I found that it Parsing Workspace is extremely slower than previous version. My workSpace has about 100000 C source files.

1. Why cpptools 1.20.5 verison feels slow than previous version?
2. what is strategy of when Updating IntelliSense and Parsing Workspace? will it updating of the file on the workspace or only update the and parse the open file?
3. Would it be possible to add a setting that allows the user to specify number of thread to use for parsing?

Steps to reproduce:

1. Open the workspce which has about 100000 C source Files using vscode 1.89.0 and cpptools 1.20.5
2. Count the time it takes to finish update Intellisense and Parsing workspace.
3. compare the time with privous version of vscode and cpptools

Expected behavior:
update Intellisense and Parsing workspace faster

Configuration and Logs

default config

Other Extensions

No response

Additional context

No response