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Description of problem:
The performance in latest rhel9.1 degraded ~30% for luks+blk with write + 64k block size + 8 Iodepth compared to rhel9.0.

While for raw or qcow2, there is no such degradation.

For details, please refer to:
http://kvm-perf.englab.nay.redhat.com/results/regression/xfs9.1.0_qemu7.0.0-9_kernel5.14.0-130/02/luks.virtio_blk.*.x86_64.html 


Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
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Actual results:

Expected results:

Additional info:

Hi Stefan,

After bisection test, the degradation is invovled firstly in qemu-kvm-core-7.0.0-1.el9. Could you please help to check in the code side? The details refer to below please.

http://kvm-perf.englab.nay.redhat.com/results/regression/xfs9.1.0_qemu7.0.0-9_kernel5.14.0-130/01/luks.virtio_blk.*.x86_64.html 

Thanks.

I have started looking at this. There are lots of code changes between qemu-kvm-6.2.0-9.el9 and qemu-kvm-7.0.0-1.el9 but nothing immediately obvious for the crypto (luks) driver.

I'll try to reproduce this issue locally so that I can profile it and experiment with code changes.

I attempted to reproduce the issue but don't measure a significant difference between qemu-kvm-6.2.0-9.el9 and qemu-kvm-7.0.0-1.el9 in the write bs=64k iodepth=8 numjobs=16 benchmark.

Maybe the bottleneck only occurs in certain environments.

Are you able to provide access to a host where the performance differences between qemu-kvm-6.2.0-9.el9 and qemu-kvm-7.0.0-1.el9 is visible? Thanks!

I have also tried 2 machines to reproduce this bug(one of them is the right one which is used while reporting the bug), but I can not reproduce it, either.

So I will close this bug now. Thanks Stefan.

http://kvm-perf.englab.nay.redhat.com/results/regression/xfs9.1.0_qemu7.0.0-9_kernel5.14.0-130/newnew/luks.virtio_blk.*.x86_64.html