Amend profiling documentation

doc/developing/misc.md

@@ -4,7 +4,7 @@
 
 We will be using a tool called "perf", which you can get by installing `perf` or `linux-perf` or `linux-tools-common`.
 
-For best results build Minetest and Irrlicht with debug symbols
+To get usable results you need to build Minetest with debug symbols
 (`-DCMAKE_BUILD_TYPE=RelWithDebInfo` or `-DCMAKE_BUILD_TYPE=Debug`).
 
 Run the client (or server) like this and do whatever you wanted to test:
@@ -17,3 +17,22 @@ This will leave a file called "perf.data".
 You can open this file with perf built-in tools but much more interesting
 is the visualization using a GUI tool: **[Hotspot](https://github.com/KDAB/hotspot)**.
 It will give you flamegraphs, per-thread, per-function views and much more.
+
+### Remote Profiling
+
+Attach perf to your running server, press *^C* to stop:
+```bash
+perf record -z --call-graph dwarf -F 400 -p "$(pidof minetestserver)"
+```
+
+Collect a copy of the required libraries/executables:
+```bash
+perf buildid-list | grep -Eo '/[^ ]+(minetestserver|\.so)[^ ]*$' | \
+	tar -cvahf debug.tgz --files-from=- --ignore-failed-read
+```
+
+Give both files to the developer and also provide:
+* Linux distribution and version
+* commit the source was built from and/or modified source code (if applicable)
+
+Hotspot will resolve symbols correctly when pointing the sysroot option at the collected libs.