perf-trace: improving ioctl details

[David Ahern]

Hi Arnaldo, Namhyung:

I have a couple of patches to perf-trace to improve the details on ioctl
calls. The first one tracks stats by individual filenames, and for the
summary output prints the ioctl stats per filename.

The second patch improves the output for the _IOC_NR element of the op
argument. For flexibility across kernel versions and drivers, it adds
the ability to read input files that contain the conversion from number
to human readable name. The files (if the option is set) are parsed at
start up. In addition to the summary, the cache is also used to improve
the readability of each ioctl line.

Questions for you:
1. is such an open ended design acceptable for perf-trace?

2. if yes, is there any preference on file format (json, yaml,
key-value, ...)?

Thanks,
David