[infinispan-dev] ClockService

[Manik Surtani]

Thinking about Sanne's idea re: a clock service and not continuously relying on System.cTM, I stumbled upon this:

https://blogs.oracle.com/ksrini/entry/we_take_java_performance_very

The last section re: caching is interesting.

Having all code use a Clock.currentTimeMillis() and having an implementation that kicks off a scheduled task to update a cached value every $frequency millis (by using the System call) is probably the correct way to implement something like this, but this adds complexities/concerns:

* CPU cache line blowing away (see article)
* Context switching
* Managing an extra service thread
* Probably an additional configuration option to configure that thread, its priority and frequency.  If frequency is dropped (e.g., every second) I suppose the perf gains would be huge.

JGroups - does JGroups make many and frequent calls to System.cTM as well?

Cheers
Manik
--
Manik Surtani
manik at jboss.org
twitter.com/maniksurtani

Platform Architect, JBoss Data Grid
http://red.ht/data-grid