Switch to CLOCK_MONOTONIC_RAW clock source

This source, available just in Linux, is similar to CLOCK_MONOTONIC, but
provides access to a raw hardware-based time that is not subject to
NTP adjustments.

Signed-off-by: Patrick Bellasi <derkling@gmail.com>
Set end workload time per workload

Each workload sets its own end time, thus allowing to have "better tuned"
workload durations according to command line configuration.

Signed-off-by: Patrick Bellasi <derkling@gmail.com>
Bugfix end time checking

This is a dummy patch to check for fractional part of end time seconds.

Signed-off-by: Patrick Bellasi <derkling@gmail.com>
Bugfix timesepc_older definition

A time S is older than E if S is greater or _equal_ to E.

Signed-off-by: Patrick Bellasi <derkling@gmail.com>
Reduce startup latency

Signed-off-by: Patrick Bellasi <derkling@gmail.com>
Reset start time once all threads have been actually started

Signed-off-by: Patrick Bellasi <derkling@gmail.com>
Add notice of tests being running

Signed-off-by: Patrick Bellasi <derkling@gmail.com>