[jboss-jira] [JBoss JIRA] Created: (JGRP-1104) Revisit critical path in NAKACK

Tue Nov 24 12:17:30 EST 2009

Revisit critical path in NAKACK
-------------------------------

                 Key: JGRP-1104
                 URL: https://jira.jboss.org/jira/browse/JGRP-1104
             Project: JGroups
          Issue Type: Task
    Affects Versions: 2.8
            Reporter: Vladimir Blagojevic
            Assignee: Vladimir Blagojevic
             Fix For: 2.9

Revisit NAKACK#handleMessage and see if we can:

a) lower contention on NRW lock by not attempting to propel up oob messages one-by-one

I have no profiling data so I am speaking without a solid proof to back my claims. I am envisioning both oob and regular threads contending for a window as they push messages up the stack. oob threads are always going to attempt to lock per message (line 788). In an event that we received missing oob message in a series of oob messages we are going to repeatedly lock window per message traversed. Not good. We don't need this IMHO. I really like lock efficient removeMany algorithm. Let removeMany propel messages up the stack as much as possible, even oob messages.

b) why are we propelling oob messages on a timer (line 833)? Is it to lower the workload of the current thread, or is there a more fundamental reason?

c) undelivered_msgs is complicating things unnecessarily IMHO. Why don't we let oob threads go into removeMany code and remove as much messages as they can - both oob and regular and push them up rather than lock NRW per message? 

-- 
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators: https://jira.jboss.org/jira/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira