[jboss-jira] [JBoss JIRA] (JGRP-1763) TimeService

TimeService ----------- Key: JGRP-1763 URL: https://issues.jboss.org/browse/JGRP-1763 Project: JGroups Issue Type: Feature Request Reporter: Bela Ban Assignee: Bela Ban Fix For: 3.5 New service which provides wall clock time at a coarse (configurable) granularity. Motivation: {{System.currentTimeMillis()}} or {{System.nanoTime()}} is sometimes called frequently, e.g. by {{TCPConnectionMap$TCPConnection.updateLastAccessed()}} or in FD/FD_ALL. This has a cost, especially when a lock is held (system calls while a lock is held cause preemption and the thread losing its time slice). However, the 2 examples above don't need the exact time, but an approximation of it is OK. GOALS: * Provide a time service which returns the last cached value of {{System.timeCurrentMillis()}} * This is a quick and efficient call * {{TimeService}} registers a timer task which updates its internal cached value every N milliseconds (configurable), e.g. every 500 ms BENEFIT: For example, in TCPConnection, the timestamp is updated whenever we send or receive a message from the peer. The timestamp is used to expire and close a connection (if configured), and can be updated 100'000 times a second. If the time service provided the current time in ms every 500ms, then {{System.currentTimeMillis()}} would only be called 2 times during a second instead of 100'000 times !