sound: latency and synchronization measurements

[ Please keep me in CC as I'm not subscribed to the list] Hi All, I am trying to characterize the audio synchronization between two systems. There is a mechanism to route audio between two systems, we run ‘aplay’ at one system and ‘arecord’ in other system. We need to measure the time difference when audio sample is out at one port and arriving at another port in different system. I plan to add printk’s in “struct snd_pcm_ops” call backs, but does these call backs tells when it received first and last audio frames\samples? Or else please suggest any other best method. -- Thanks, Sekhar