diff --git a/test/lang/README.md b/test/lang/README.md
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+# Performance and tail-call optimization status
+
+```log
+Function: fib(40)
+-----------------------------------------------------
+ Device:    Lenovo Ideapad 720s [i5-8250U @ 1.60GHz]
+-----------------------------------------------------
+Linux       x64   gcc 7.4.0       4.63s
+Linux       x64   clang 9         5.32s
+Win 10      x64   msvc 2019           ?
+Win 10      x64   clang               ?
+Linux       x86   gcc            11.34s
+Linux       x86   clang          15.37s  - no TCO
+Win 10      x86   msvc                ?
+Win 10      x86   clang               ?
+--- other wasm engines
+WAVM        x64   0.8.0           0,62s
+wasmer      x64   0.8.0           0.70s
+V8          x64   Node.js         0.74s
+V8          x64   Chrome          0.74s
+SpMonkey    x64   JS Shell        0.93s
+iwasm       x64                  25.70s  - interp
+wac         x64                  37.11s  - interp
+--- other languages
+C           x64   gcc             0.23s  - native
+Lua         x64   LuaJIT          1.15s  - jit
+JS          x64   Node v10.15     2.97s  - jit
+Lua         x64   Lua 5.1        16.65s
+Python      x64   2.7            34.08s
+Python      x64   3.4            35.67s
+Micropython x64   v1.11          85,00s
+Espruino    x64   2v04          >10 min
+```
+
+```log
+-----------------------------------------------------
+ Device:    Raspberry Pi 4 [BCM2711B0 A72 @ 1.5GHz]
+-----------------------------------------------------
+Linux      armv7l gcc 8.3        23.78s
+```
+
+```log
+-----------------------------------------------------
+ Device:    ESP32 [ESP32D0WDQ5 Xtensa LX6 @ 240MHz]
+-----------------------------------------------------
+ESP-IDF     lx6   gcc             17.9m  - no TCO, and yes, minutes! ;)
+
+```
+
+## Running
+
+```sh
+# WAC
+time $(ENGINES_PATH)/wac/wac fib.wasm _fib 40
+
+# WAMR
+time $(ENGINES_PATH)/wasm-micro-runtime/core/iwasm/products/linux/build/iwasm -f _fib fib.wasm 40
+
+# Wasmer
+time wasmer run --em-entrypoint _fib fib.wasm -- 40
+
+# WAVM
+time $(ENGINES_PATH)/wasm-jit-prototype/_build/bin/wavm run -f _fib fib.wasm 40
+```