Added pprof tool (#2512)

docs/PROFILING.md

@@ -0,0 +1,24 @@
+# Telegraf 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.
+
+By default, the profiling is turned off.
+
+To enable profiling you need to specify address to config parameter `pprof-addr`, for example:
+
+```
+telegraf --config telegraf.conf --pprof-addr localhost:6060
+```
+
+There are several paths to get different profiling information:
+
+To look at the heap profile:
+
+`go tool pprof http://localhost:6060/debug/pprof/heap`
+
+or to look at a 30-second CPU profile:
+
+`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.
+