Rust profiling RFC

design/0005-rust-profiling.md

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+# Title
+
+Add Profiling to the Linkerd Policy Controller
+
+## Problem
+
+Enabling users to dynamically profile the running application, which can aid
+significantly in debugging and diagnostics. This will allow users to identify
+and address performance bottlenecks or other issues in real-time and they can
+act accordingly.
+
+## Desired Outcome
+
+With the new CLI arguments that enable pprof, users will be able to profile
+resource consumption of individual controllers and gain insights into how the
+policy-controller is operating.
+
+## Potential Solution
+
+__Integrate [pprof-rs](https://github.com/tikv/pprof-rs/blob/master/README.md)
+into the Linkerd Proxy-controller__: pprof-rs is a profiling tool for Rust that
+can be used to generate CPU profiles and heap snapshots. It can be integrated
+into the Linkerd control plane to provide dynamic profiling capabilities to
+users. This will involve adding the pprof-rs library as a dependency and
+modifying the controllers to support pprof-rs. Create a new CLI argument that
+tells the controller to enable-pprof profiling. Parse the new CLI argument and
+start the ProfilerGuard if the argument is present. Implement a route that
+exposes the profiling endpoint using the pprof crate.
+
+## Prior Art
+
+Pyroscope itself is a profiler tool which uses pprof-rs for profiling Rust code.