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From "Jonathan Valliere (JIRA)" <j...@apache.org>
Subject [jira] [Comment Edited] (DIRMINA-1095) Seems like the management f UDP sessions is really unneficient
Date Mon, 01 Oct 2018 14:54:00 GMT

    [ https://issues.apache.org/jira/browse/DIRMINA-1095?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16634143#comment-16634143
] 

Jonathan Valliere edited comment on DIRMINA-1095 at 10/1/18 2:53 PM:
---------------------------------------------------------------------

The code as-is only performs that scheduling loop when the SelectionKey returns isWritable().
 This is an optimization right there to prevent the scheduling from occurring every single
time the SelectionKey is awake.  Either the NioSessions should be associated to a specific
DatagramChannel and optimize there by only looping on ones belonging to that specific DatagramChannel
or nothing should be done.  Either way, unless you are binding to lots of ports; any performance
benefit from the association optimization would be minimal.


was (Author: johnnyv):
The code as-is only performs that scheduling loop when the SelectionKey returns isWritable().
 This is an optimization right there to prevent the scheduling from occurring every single
time the SelectionKey is awake.  Either the NioSessions should be associated to a specific
DatagramChannel and optimize there by only looping on ones belonging to that specific DatagramChannel
or nothing should be done.

> Seems like the management f UDP sessions is really unneficient
> --------------------------------------------------------------
>
>                 Key: DIRMINA-1095
>                 URL: https://issues.apache.org/jira/browse/DIRMINA-1095
>             Project: MINA
>          Issue Type: Improvement
>    Affects Versions: 2.0.19
>            Reporter: Emmanuel Lecharny
>            Priority: Major
>             Fix For: 2.0.20
>
>
> When we process incoming UDP messages, we iterate over the activated {{SelectionKey}}s.
That's ok, but for each one of them, we read the data and try to flush the scheduled messages.
The loop where it's done seems to iterate on *all* the managed sessions, for each keys we
are processing :
> {code:java}
>    private void processReadySessions(Set<SelectionKey> handles) {
>         Iterator<SelectionKey> iterator = handles.iterator();
>         while (iterator.hasNext()) {
>             SelectionKey key = iterator.next();
>             DatagramChannel handle = (DatagramChannel) key.channel();
>             iterator.remove();
>             try {
>                 if (key.isValid() && key.isReadable()) {
>                     readHandle(handle);
>                 }
>                 if (key.isValid() && key.isWritable()) {
>                     for (IoSession session : getManagedSessions().values()) {
>                         scheduleFlush((NioSession) session);
> ...
> {code}
> There is no reason to do so. First, we should not iterate on all the managed sessions
(we may have thousands), but only the sessions which have something to write, and we certainly
should not do that for every active key...



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