[jboss-jira] [JBoss JIRA] Commented: (JGRP-1043) UNICAST: high contention

[ https://jira.jboss.org/jira/browse/JGRP-1043?page=com.atlassian.jira.plug... ] Brian Stansberry commented on JGRP-1043: ---------------------------------------- As discussed on our chat, a semi-related issue is if a retransmission of a message that's already been acked comes in to a receiver, the receiver acks it resulting in an ack messages with a seqno lower than the highest. When that ack is received the current AckSenderWindow.ack will reset it's "lowest" field to that lower seqno, with the result that the *next* normal ack will loop a lot trying to remove already removed entries. The following is a potential impl that handles this: /** * Removes all messages <em>less than or equal</em> to seqno from <code>msgs</code>, and cancels their retransmission. */ public synchronized void ack(long seqno) { if(lowest == 0) { Long tmp=getLowestSeqno(); if(tmp != null) lowest=tmp; } if (seqno >= lowest) { for(long i=lowest; i <= seqno; i++) { msgs.remove(i); retransmitter.remove(i); } lowest=seqno +1; } else { // We already received an ack for a higher seqno; this should // be an ack for a retransmission. We should have already // cleaned up when we got the higher seqno ack, but as a // second line of defense, do it again msgs.remove(seqno); retransmitter.remove(seqno); } } -- 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