[Bug]: latency regression

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Preliminary Actions

• [X] I have searched the existing issues and didn't find a duplicate.
• [X] I have followed the AWS official troubleshoot documentation.
• [X] I have followed the driver readme and best practices.

Driver Type

Linux kernel driver for Elastic Network Adapter (ENA)

Driver Tag/Commit

ena_linux_2.12.0-1-gf9303af

Custom Code

No

OS Platform and Distribution

Linux 6.8.9-1.el8.elrepo.x86_64

Bug description

There's big latency regression when going from default driver in rocky 8 linux to newest 2.12.0g version for UDP. TCP round-trip latency estimations show around 50-60us for both drivers, while UDP increases from ~45us to over 100us. We tested both stock 2.12.0g and with zero-copy patch applied, the difference is neglible.

Reproduction steps

1. Create rocky 8 instance
2. Upgrade kernel to newest ml
3. Run any round-trip test
4. reload kernel module
4. rerun test

Expected Behavior

No regression or ideally increase of performance

Actual Behavior

Greatly increased latency

Additional Data

1. eu-west-1a
2. c5n.metal
3. i-0b7b6e2883541a7f6, i-0a7e5017160ddcfac

Relevant log output

No response

Contact Details

[email protected]