[jboss-jira] [JBoss JIRA] (JGRP-1601) TP: message bundling based on count per dest rather than global count

[Bela Ban (JIRA)]

    [ https://issues.jboss.org/browse/JGRP-1601?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12756460#comment-12756460 ] 

Bela Ban commented on JGRP-1601:
--------------------------------

The downside is that if we a large stream of messages (so we're only terminating a bundle on reaching max_bundle_size for a given dest) and a large number of different destinations, then it will take longer to fill an individual destination, ie. to send the message bundle.

This might be OK for async calls, but would slow sync RPCs down.

Possibly create a subclass of TransferQueueBundler and measure perf with the 2 different bundler types. The goal, however, should be to only have 1 bundler.
                
> TP: message bundling based on count per dest rather than global count
> ---------------------------------------------------------------------
>
>                 Key: JGRP-1601
>                 URL: https://issues.jboss.org/browse/JGRP-1601
>             Project: JGroups
>          Issue Type: Enhancement
>            Reporter: Bela Ban
>            Assignee: Bela Ban
>             Fix For: 3.3
>
>
> Currently, the message bundlers in TP count accumulated message sizes based on a global 'count' variable. So both multicast messages, and messages to A, B and C increment count.
> If we only sent a message bundle to destination T if (1) there are no more messages in the queue or (2) the accumulated bytes for T would exceed max_bundle_size, then we might send more batches and fewer individual messages.
> Example:
> * We're sending 10K messages and max_bundle_size=55K
> * Different threads concurrently send
> ** T1: 6 multicast messages
> ** T2: 6 messages to A
> ** T3: 6 messages to B
> ** T4: 6 messages to C
> ** T5: 6 messages to D
> ** T6: 6 messages to E
> * If each of the threads gets 1 message in, we've reached the max_bundle_size and will send a message bundle for the multicast, 1 bundle for the unicast message to A, 1 for the message to B and so on, for a total of 5 bundles with *one* message only !
> * If we counted bytes per destination, we'd be able to send a bundle of 5 messages to the multicast dest, 5 to A, 5 to B and so on.
> ** This might lead to better performance, as message batches on the receivers tend to be filled better, especially if we have many messages being sent concurrently.
> With a counter per dest we'd ideally send 6 message batches (containing 6 messages each); whereas with 1 count variable we'd send 36 batches each containing only 1 message !
> Investigate whether it would make sense (perf-wise) to have count being associated with individual destinations rather than having a global count variable.

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