Comment 2 for bug 634306

I have done more research on this with shell scripting, and based on performance analysis techniques I think we need the following, which is quite similar to /proc/diskstats (http://www.mjmwired.net/kernel/Documentation/iostats.txt):

pending

   The number of sessions for which there has been a request but there is no response yet.

busytime

   The total elapsed time during which there was at least one pending request. This increases while pending is nonzero.

weighted

   The total response time consumed by all requests, including those that are not yet complete.

There is an 'awk' implementation of this in the following script: http://aspersa.googlecode.com/svn/trunk/usl Look at the convert_tcpdump_tabulate() function.