[LU-14424] write performance regression in Lustre-2.14.0-RC1

• Type: Bug
• Resolution: Fixed
• Priority: Critical
• Fix Version/s: Lustre 2.14.0
• Affects Version/s: Lustre 2.14.0
• Severity: 2
• Assignee: Shuichi Ihara
• Reporter: Shuichi Ihara

Description

While I was runnng the performance regression tests, a performance regression in Lustre-2.14.0-RC1 was found on the write with 4K transfer size.
Here is a reproducer and test results.

# mpirun -np $NP -mca btl_openib_if_include mlx5_1:1 -x UCX_NET_DEVICES=mlx5_1:1 --allow-run-as-root /work/tools/bin/ior -w -r -t 4k -b $((256/NP)) -e -v -F -o /ai400x/ior.out/file

Client Version	NP	Write(MB/s)	Read(MB/s)
Lustre-2.13.0	1	803	3293
Lustre-2.14.0-RC1	1	529	3092
Lustre-2.13.0	16	6962	12021
Lustre-2.14.0-RC1	16	5127	11951

Issue Links

• is related to: LU-14443 review-dne-ssk test session failed: Error checking ski of cli2mdt
• is related to: LU-9679 Prepare lustre for adoption into the linux kernel