vktm process high cpu usage

Hello,

While installing 12c grid infrastructure, observed that vktm and LMS process are consuming high CPU

top - 23:48:23 up  4:58,  4 users,  load average: 13.38, 13.80, 12.08
Tasks: 217 total,   2 running, 215 sleeping,   0 stopped,   0 zombie
Cpu(s): 27.5%us, 26.1%sy,  0.0%ni,  0.7%id,  0.7%wa,  0.0%hi, 45.1%si,  0.0%st
Mem:   3519360k total,  3416516k used,   102844k free,    38652k buffers
Swap:  3522556k total,    51436k used,  3471120k free,  2031560k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
16699 oracle    -2   0 1369m  16m  14m S 54.8  0.5  11:43.68 asm_vktm_+ASM1
16719 oracle    -2   0 1383m  32m  19m S  9.0  0.9   1:57.39 asm_lms0_+ASM1

[oracle@Geek DBA12c-rac1 ~]$ vmstat 5 5
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
11  0  51436  98760  39500 2039132    0    8  2047  2113  642  842 22 63 11  4  0
 7  0  51544 103152  39504 2035180    0   22     1    69  275  825 26 74  0  0  0
12  0  51544 105036  39512 2035560    0    0    52    28  259  857 26 73  0  0  0
17  0  51544 104968  39520 2035652    0    0     1    29  260  795 25 75  0  0  0
 7  0  51544 104664  39528 2035716    0    0    10   136  259  767 24 76  0  0  0

This is expected nature in vm environments (mine is a linux guest OS on Virtual Box) To fix this

*** Do not do it on Production Systems ****

[oracle@Geek DBA12c-rac1 ~]$

SQL> select ksppstvl from x$ksppi join x$ksppcv using (indx) where ksppinm='_high_priority_processes';

KSPPSTVL
--------------------------------------------------------------------------------
LMS*|VKTM


SQL> alter system set "_high_priority_processes"='' scope=spfile;

System altered.

After the bounce of ASM and clusterware the cpu usage fot VKTM came down and the usage back to normal.

Hope this helps