Details
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Bug
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Resolution: Fixed
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Major
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Lustre 2.14.0
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None
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master (commit: 56526a90ae)
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3
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9223372036854775807
Description
commit 76626d6c52 "LU-13344 all: Separate debugfs and procfs handling" caused write performance regression. Here is a reproducer and tested workload.
Single Client(Ubuntu 18.04, 5.4.0-47-generic), 16MB O_DIRECT, FPP (128 processes)
# mpirun --allow-run-as-root -np 128 --oversubscribe --mca btl_openib_warn_default_gid_prefix 0 --bind-to none ior -u -w -r -k -e -F -t 16384k -b 16384k -s 1000 -u -o /mnt/ai400x/ior.out/file --posix.odirect
"git bisect" indentified an commit where regression started.
Here is test results.
76626d6c52 LU-13344 all: Separate debugfs and procfs handling
access bw(MiB/s) IOPS Latency(s) block(KiB) xfer(KiB) open(s) wr/rd(s) close(s) total(s) iter ------ --------- ---- ---------- ---------- --------- -------- -------- -------- -------- ---- write 21861 1366.33 60.78 16384 16384 0.091573 93.68 40.38 93.68 0 read 38547 2409.18 46.14 16384 16384 0.005706 53.13 8.26 53.13 0
5bc1fe092c LU-13196 llite: Remove mutex on dio read
access bw(MiB/s) IOPS Latency(s) block(KiB) xfer(KiB) open(s) wr/rd(s) close(s) total(s) iter ------ --------- ---- ---------- ---------- --------- -------- -------- -------- -------- ---- write 32678 2042.40 58.96 16384 16384 0.105843 62.67 4.98 62.67 0 read 38588 2411.78 45.89 16384 16384 0.004074 53.07 8.11 53.07 0
master (commit 56526a90ae)
access bw(MiB/s) IOPS Latency(s) block(KiB) xfer(KiB) open(s) wr/rd(s) close(s) total(s) iter ------ --------- ---- ---------- ---------- --------- -------- -------- -------- -------- ---- write 17046 1065.37 119.02 16384 16384 0.084449 120.15 67.76 120.15 0 read 38512 2407.00 45.04 16384 16384 0.006462 53.18 9.07 53.18 0
master still has this regression and when commit 76626d6c52 reverts from master, the performrance is back.
master (commit 56526a90ae)+ revert commit 76626d6c52
access bw(MiB/s) IOPS Latency(s) block(KiB) xfer(KiB) open(s) wr/rd(s) close(s) total(s) iter ------ --------- ---- ---------- ---------- --------- -------- -------- -------- -------- ---- write 32425 2026.59 59.88 16384 16384 0.095842 63.16 4.79 63.16 0 read 39601 2475.09 47.22 16384 16384 0.003637 51.72 5.73 51.72 0
