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Long-running iperf3 client triggers out-of-memory on guest

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Abstract

An Ubuntu 26.04 guest is configured with a single bridge interface. The iperf3 server is started on the host and the iperf3 client is initiated on the guest, connecting to the host through the bridge Internet Protocol (IP) with an 8000 second test duration. Within the first two hours of execution, the guest experiences an out-of-memory condition that is accompanied by a sudden memory usage spike.

Content

Linux Releases Affected

Ubuntu 26.04 and later

IBM Systems Affected

All Power10 and Power11 systems that run on FW1110 or later

Symptoms

General sluggishness and out-of-memory (OOM) getting triggered while running a heavy network workload.

Workaround

No workaround is available.

Fix Outlook

LP2143080

The problem is specific to Ubuntu kernel and not present in upstream Linux kernel. The fix for this issue will be included in a later release.

I/O device impacted

None

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Document Information

Modified date:
04 May 2026

UID

ibm17269909

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