Bug type: Language Service

• OS and Version: Windows10 (Version 2004)
• VS Code Version: 1.58.2
• C/C++ Extension Version: v1.5.1

"Go To Symbol in Workspace..."(CTRL+T) is very slow on large projects.

As a benchmark, I opened a workspace on Linux code base, and searched for "memory".
Results for the first search are abnormally long (~25 seconds)

Notes:

1. I set C_Cpp.intelliSenseEngine to "Tag Parser" (my preferred choice)
2. The workspace was fully parsed before running the search.
3. For comparison, on Source Insight IDE, results for the same symbol search are instant (<1s).

Expected behavior
Full Workspace Symbols Search should return results faster