[LU-9905] cpu_npartitions is not configured properly

• Status: Resolved
• Project: Lustre
• Affects Version/s: Lustre 2.10.0
• Type: Bug
• Priority: Minor
• Reporter: Shuichi Ihara (Inactive)
• Assignee: Dmitry Eremin (Inactive)
• Resolution: Not a Bug
• Severity: 3

Description

cpu_npartitions=10 is configured manually, but after re-loaded module, never cpu_partition_table changed.

[root@oss01 ~]# umount -t lustre -a; lustre_rmmod

[root@oss01 ~]# cat /etc/modprobe.d/lustre.conf 
options lnet networks="o2ib10(ib0)"
options libcfs cpu_npartitions=10

[root@oss01 ~]# mount -t lustre 10.0.10.167@o2ib10:10.0.10.168@o2ib10:/scratch /scratch -o localflock 
[root@oss01 ~]# cat /proc/sys/lnet/cpu_partition_table 
0	: 0 2 4 6 8 10 12 14 16 18
1	: 1 3 5 7 9 11 13 15 17 19

Comments

[Peter Jones]

Dmitry

Can you please advise on this one?

Thanks

Peter

[Dmitry Eremin (Inactive)]

Sorry for delay. This behavior is expected. Resently we changed the default value for CPU partitions.

https://review.whamcloud.com/22507

So, now cpu_pattern is specified and have default value "N". But if cpu_pattern is specified, the cpu_npartitions will be ignored.

You can return to previous behavior by spefifing empty value for cpu_pattern.

So, please use the following configuration:

options libcfs cpu_pattern="" cpu_npartitions=10

[Shuichi Ihara (Inactive)]

ok, that workaround works. you can close this ticket.
However, after patch 22507 landed, default partition configuation for MDS caused huge performance regression. please check LU-9998.