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https://issues.apache.org/jira/browse/QPID-8772?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Daniil Kirilyuk updated QPID-8772:
----------------------------------
    Fix Version/s: qpid-java-broker-10.2.0

> [Broker-J] Excessive CPU usage from continuous rescheduling of blocked 
> TCP/TLS writes
> -------------------------------------------------------------------------------------
>
>                 Key: QPID-8772
>                 URL: https://issues.apache.org/jira/browse/QPID-8772
>             Project: Qpid
>          Issue Type: Bug
>          Components: Broker-J
>    Affects Versions: qpid-java-broker-10.1.1
>            Reporter: Kato Kaito
>            Priority: Minor
>             Fix For: qpid-java-broker-10.2.0
>
>         Attachments: qpid-8772-jmh-main.zip
>
>
> Deployments with many concurrent AMQP connections can experience write 
> backpressure when some clients consume data slowly or communicate over 
> constrained network paths, such as VPNs or TCP proxies. In these conditions, 
> outbound data remains buffered while the broker waits for clients to receive 
> it.
> The native TCP/TLS transport can repeatedly reschedule a connection with 
> pending output without waiting for the socket to become writable. This causes 
> repeated write attempts even when the connection cannot make progress. A 
> stale partial-read indication can also keep a connection scheduled when 
> subsequent processing skips reads.
> This behavior can consume significant CPU despite limited network throughput 
> and occupy I/O workers needed by other connections. The impact is 
> particularly relevant when several slow connections share an I/O pool with 
> otherwise healthy clients.
> TLS requires an additional distinction: pending application output may be 
> waiting for peer handshake data rather than socket write capacity. In this 
> case, write readiness cannot advance the connection; the transport must allow 
> reads and wait for incoming data.



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