Oracle Operating System Watcher Black Box (OSWbb) 5 is available (as a free download from Oracle Support, see document 301137.1) which supports regular automated collection of Operating Level statistics (eg. vmstat, iostat, top, etc) on *nix-based systems. This tool provides all of the required collectors as well as the scripts required to analyse the collected data, and highlight potential bottlenecks and hotspots at the OS/Architecture level.
I recommend reviewing the implementation and usage documentation attached with this download before deploying it on your installations.
The use of this tool can simplify the initial stages of performance tuning and analysis, and allow for a standardised output in terms of the performance report artifact produced, whilst potentially allowing the Performance tuning team to focus their efforts on the rest of the application stack.
Whilst it is recognised that this is by no means a complete solution to the analysis of the OS and Architecture layer, it does form a starting point for further investigation, by highlighting areas of concern.