docs: Update profiling docs (#15369)

Co-authored-by: Dane Strandboge <136023093+DStrand1@users.noreply.github.com>

docs/PROFILING.md

@@ -1,23 +1,57 @@
-# Telegraf profiling
+# Profiling
 
-Telegraf uses the standard package `net/http/pprof`. This package serves via its HTTP server runtime profiling data in the format expected by the pprof visualization tool.
+Telegraf uses the standard package `net/http/pprof`. This package serves via
+its HTTP server runtime profiling data in the format expected by the pprof
+visualization tool.
 
-By default, the profiling is turned off.
+## Enable profiling
 
-To enable profiling you need to specify address to config parameter `pprof-addr`, for example:
+By default, the profiling is turned off. To enable profiling users need to
+specify the pprof address config parameter `pprof-addr`. For example:
 
 ```shell
 telegraf --config telegraf.conf --pprof-addr localhost:6060
 ```
 
-There are several paths to get different profiling information:
+## Profiles
+
+To view all available profiles, open the URL specified in a browser. For
+example, open `http://localhost:6060/debug/pprof/` in your browser.
 
 To look at the heap profile:
 
-`go tool pprof http://localhost:6060/debug/pprof/heap`
+```shell
+go tool pprof http://localhost:6060/debug/pprof/heap
+```
 
-or to look at a 30-second CPU profile:
+To look at a 30-second CPU profile:
 
-`go tool pprof http://localhost:6060/debug/pprof/profile?seconds=30`
+```shell
+go tool pprof http://localhost:6060/debug/pprof/profile?seconds=30
+```
 
-To view all available profiles, open `http://localhost:6060/debug/pprof/` in your browser.
+## Generate heap image
+
+It is very helpful to generate an image to visualize what heap memory is used.
+It is best to capture an image a few moments after Telegraf starts and then at
+additional periods (e.g. 1min, 5min, etc.).
+
+A user can capture the image with Go via:
+
+```shell
+go tool pprof -png http://localhost:6060/debug/pprof/heap > heap.png
+```
+
+The resulting image can be uploaded to a bug report.
+
+## References
+
+For additional information on pprof see the following:
+
+* [net/http/pprof][]
+* [Julia Evans: Profiling Go programs with pprof][]
+* [Debugging Go Code][]
+
+[net/http/pprof]: https://pkg.go.dev/net/http/pprof
+[julia evans: profiling go programs with pprof]: https://jvns.ca/blog/2017/09/24/profiling-go-with-pprof/
+[Debugging Go Code]: https://www.infoq.com/articles/debugging-go-programs-pprof-trace/