[clang] [analyzer][docs] Document how to use perf and uftrace to debug performance issues (PR #126520)

[Gábor Horváth via cfe-commits]

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@@ -45,3 +48,91 @@ Note: Both Chrome-tracing and speedscope tools might struggle with time traces a
 Luckily, in most cases the default max-steps boundary of 225 000 produces the traces of approximately that size
 for a single entry point.
 You can use ``-analyze-function=get_global_options`` together with ``-ftime-trace`` to narrow down analysis to a specific entry point.
+
+
+Performance analysis using ``perf``
+===================================
+
+`Perf <https://perfwiki.github.io/main/>`_ is an excellent tool for sampling-based profiling of an application.
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Xazax-hun wrote:

While I agree that `perf` is excellent, I wonder if we in general want to stay away from value judgements in documentation. 

https://github.com/llvm/llvm-project/pull/126520