gbsim/loopback: update test utility to log all latency data to file
gbsim/loopback: update test utility to log all latency data to file

A kernel update ('greybus/loopback: provide interface to read all latency
data-points') provides a character device interface that allows user-space
to read out all of the logged latency value for a given data run.

This patch updates the C test driver to pull that data out and log it to
CSV file.

Format of the CSV file now will be

date:                         Datestamp of the test
type:                         ping, transfer or sink
size:                         Size of payload in bytes, ignored with ping
iteration_max:                The number of iterations for the test
error:                        Number of greybus operation errors
requests_per_second_min:      Minimum measured requests per second
requests_per_second_max:      Maximum measured requests per second
requests_per_second_avg:      Average measured requests per second
requests_per_second_jitter:   Jitter between min and max measured
                              requests per second
latency_min:                  Minimum measured latency
latency_max:                  Maximum measured latency
latency_avg:                  Average measured latency
latency_jitter:               Jitter between min and max latency
throughput_min:               Minimum measured bytes-per-second throughput
throughput_max:               Maximum measured bytes-per-second throughput
throughput_avg:               Average measured bytes-per-second throughput
thoughput_jitter:             Jitter between min and max measured
                              bytes-per-second throughput
raw_latencies:                1-iteration_max 32 bit numbers indicating
                              each individual greybus operation turn-around
                              time in microseconds

Signed-off-by: Bryan O'Donoghue <165dc05575478af93ac2f97f67be6e1756010094@linaro.org>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@google.com>

projectara/gbsim,bcousson/gbsim,bcousson/gbsim,bcousson/gbsim,projectara/gbsim,gregkh/gbsim,gregkh/gbsim