[LAU] rtirq - what does it improve, and how can I measure it?

[Kaj Ailomaa]

I understand that the rtirq script is designed to raise rtprio for audio 
devices, which is made possible on the vanilla kernel since 2.6.39(?), 
if passing the threadirqs option to the kernel at boot, and having built 
it with the CONFIG_FORCE_THREADIRQ.

 From my experience, I have not had any performance boost using the 
rtirq script, but I have read about it helping those who are getting 
xruns due to irq sharing.

So, I'm wondering. What picture do others have of the benefit of the 
rtirq script?

..and are there other ways to measure improvement for audio operation 
other than spotting xruns at different latency settings, and reading the 
rtprio for various devices using the 'ps' command?