Fail-safe attempts to read an ultimate statistics on removal time; if
that fails, it uses the latest recorded snapshot.
This patch adds timestamp for each stats snapshot to allow a time report
since the last snapshot in case of the above failure.
By this way, the user can estimate the stats read accuracy.
Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Gaetan Rivet <gaetan.rivet@6wind.com>