[LU-9998] Default partition setup is not optimal for best metadata performance

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.11.0, Lustre 2.10.4
• Environment: b2_10
• Severity: 3
• Assignee: Dmitry Eremin (Inactive)
• Reporter: Shuichi Ihara (Inactive)

Description

Here is MDS's CPU configuration.

[root@mds11 ~]# lscpu 
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                48
On-line CPU(s) list:   0-47
Thread(s) per core:    2
Core(s) per socket:    24
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 85
Model name:            Intel(R) Xeon(R) Platinum 8160 CPU @ 2.10GHz
Stepping:              4
CPU MHz:               2101.000
BogoMIPS:              4200.00
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              1024K
L3 cache:              33792K
NUMA node0 CPU(s):     0-47

[root@mds11 ~]# numactl -H
available: 1 nodes (0)
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
node 0 size: 96940 MB
node 0 free: 90229 MB
node distances:
node   0 
  0:  10 

only single partition created by default for single CPU configuration.

[root@mds11 ~]# cat /proc/sys/lnet/cpu_partition_table 
0	: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47

This default partition configuration is not optimal and affects huge metadata performance impact. especially stats and read operations.
Please see below test results with default and manual setting with 6 partitions.

Default partition (npartition=1)

mpirun -np 128 /work/tools/bin/mdtest -n 5000 -v -d /scratch0/dir0 -F -i 3 -p 10 -w 0 -u

SUMMARY: (of 3 iterations)
   Operation                      Max            Min           Mean        Std Dev
   ---------                      ---            ---           ----        -------
   File creation     :      90269.484      73210.911      83067.818       7212.787
   File stat         :     192519.466     191217.586     191843.135        532.702
   File read         :      84278.190      74407.351      78726.036       4123.061
   File removal      :     152552.089     141405.693     148541.612       5058.776
   Tree creation     :        576.227        129.569        332.039        184.718
   Tree removal      :         28.016         12.466         18.019          7.083
V-1: Entering timestamp...

npartition=6

[root@mds11 ~]# cat /proc/sys/lnet/cpu_partition_table 
0	: 0 1 2 3 24 25 26 27
1	: 4 5 6 7 28 29 30 31
2	: 8 9 10 11 32 33 34 35
3	: 12 13 14 15 36 37 38 39
4	: 16 17 18 19 40 41 42 43
5	: 20 21 22 23 44 45 46 47

mpirun -np 128 /work/tools/bin/mdtest -n 5000 -v -d /scratch0/dir0 -F -i 3 -p 10 -w 0 -u
SUMMARY: (of 3 iterations)
   Operation                      Max            Min           Mean        Std Dev
   ---------                      ---            ---           ----        -------
   File creation     :     130215.199     112298.894     123903.497       8216.228
   File stat         :     447219.644     422373.391     436421.078      10400.374
   File read         :     224856.656     216383.752     219513.555       3796.625
   File removal      :     142603.040     138102.147     139843.976       1973.252
   Tree creation     :        561.879        170.631        379.767        160.865
   Tree removal      :         41.908         41.042         41.509          0.357
V-1: Entering timestamp...