[jboss-jira] [JBoss JIRA] (JGRP-1989) Bundlers: reuse send buffer when transport == sync.

[Radim Vansa (JIRA)]

    [ https://issues.jboss.org/browse/JGRP-1989?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13134860#comment-13134860 ] 

Radim Vansa commented on JGRP-1989:
-----------------------------------

Now it really just passes the buffer into the queue, but in the past (looking into git history before the NIO stuff) you've copied the buffer there:
{code:java}
public void send(byte[] data, int offset, int length) throws Exception {
        if (sender != null) {
            // we need to copy the byte[] buffer here because the original buffer might get changed meanwhile
            byte[] tmp = new byte[length];
            System.arraycopy(data, offset, tmp, 0, length);
            sender.addToQueue(tmp);
        }
        else
            _send(data, offset, length, true, true);
    }
{code}

So the current state when you allocate the buffer anew is not that worse after all (besides allocating more than you need), because it just moved the invocation to bundler.

> Bundlers: reuse send buffer when transport == sync.
> ---------------------------------------------------
>
>                 Key: JGRP-1989
>                 URL: https://issues.jboss.org/browse/JGRP-1989
>             Project: JGroups
>          Issue Type: Enhancement
>            Reporter: Bela Ban
>            Assignee: Bela Ban
>             Fix For: 3.6.7
>
>
> With the addition of {{TCP_NIO2}}, all bundlers now create new send buffers for every message (or message list). This generates a lot of memory allocations, perhaps it is better to revert this change for *synchronous transports* such as {{UDP}} and {{TCP}}, and still create new buffers for *asynchronous transports* such as {{TCP_NIO2}}.
> Synchronous transports guarantee a message has been put on the wire when {{TP.send()}} returns, whereas asynchronous transports may only have completed a partial write (so we cannot reuse the buffer).
> The code in the bundler should check for this, and copy if async or not copy if sync.
> Whether or not a transport is sync is determined by a new abstract method that needs to be overridden by every transport.



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