readme: describe the requirements
@@ -9,3 +9,9 @@ $ sudo h2olog -p $(pgrep -o h2o)
```
Root privilege is required to interact with the BPF virtual machine.
+
+## Requirements
+
+- H2O server built after [886db137](https://github.com/h2o/h2o/pull/2057/commits/886db13791bb03794901710974fb52cd1238968e)
+- [BCC](https://iovisor.github.io/bcc/) (BPF Compiler Collection) [installed](https://github.com/iovisor/bcc/blob/master/INSTALL.md) on your system
+- Root privilege to execute the program
