change the reactor load metrics to utilization

utilization is a better name to describe the percentage the CPU is
loaded.

Signed-off-by: Amnon Heiman <amnon@scylladb.com>
Message-Id: <1483532937-9936-1-git-send-email-amnon@scylladb.com>

core/reactor.cc

@@ -1931,7 +1931,7 @@ void reactor::register_metrics() {
             // total_operations value:DERIVE:0:U
             sm::make_derive("tasks_processed", _tasks_processed, sm::description("Total tasks processed")),
             sm::make_derive("timers_pending", std::bind(&decltype(_timers)::size, &_timers), sm::description("Number of tasks in the timer-pending queue")),
-            sm::make_gauge("load", [this] { return _load * 100; }, sm::description("CPU load percentage")),
+            sm::make_gauge("utilization", [this] { return _load * 100; }, sm::description("CPU utilization")),
             sm::make_derive("cpu_busy_ns", [this] () -> int64_t { return std::chrono::duration_cast<std::chrono::nanoseconds>(total_busy_time()).count(); },
                     sm::description("Total cpu busy time in nanoseconds")),
             // total_operations value:DERIVE:0:U