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High CPU Utilization After Kernel Upgaded Related to pcc_cpufreq Kernel Module. (Doc ID 2470001.1)

Last updated on MAY 19, 2021

Applies to:

Linux OS - Version Oracle Linux 5.6 and later
Linux x86-64

Symptoms

After changing the current kernel from UEK3 or RHCK to UEK4 ( in this case 4.1.12-124.16.4.el6uek.x86_64)  some high CPU utilization ( SYS utilization ) is observed on the upgraded node.

From the Oswatcher data collected, ahuge number of processes waiting for run time may be the reason for the high load average.

------------------
top - 23:00:37 up 36 min, 6 users, load average: 87.02, 64.09, 42.16
top - 23:01:37 up 37 min, 7 users, load average: 85.05, 67.55, 44.72
top - 23:02:37 up 38 min, 7 users, load average: 89.42, 71.48, 47.47
top - 23:04:37 up 40 min, 8 users, load average: 106.78, 84.43, 55.11
top - 23:06:39 up 42 min, 8 users, load average: 107.62, 92.46, 61.65
top - 23:07:38 up 43 min, 8 users, load average: 102.65, 93.51, 63.92
top - 23:08:39 up 44 min, 8 users, load average: 89.74, 91.46, 65.06
top - 23:09:38 up 45 min, 9 users, load average: 88.73, 91.14, 66.62

 
zzz ***Wed Sep 26 22:44:31 EDT 2018
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
62 1 0 128409720 324996 2722752 0 0 655 270 485 96 13 9 77 1 0 <<<<<<<<<
27 0 0 128338704 325908 2758772 0 0 29765 5797 39904 49040 13 7 79 1 0
15 2 0 127981056 326704 2812644 0 0 41549 9056 61895 64322 24 17 58 1 0
zzz ***Wed Sep 26 22:45:32 EDT 2018
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
24 1 0 127915776 328936 2957688 0 0 657 267 20 134 13 9 77 1 0
13 3 0 127857952 329492 3003016 0 0 53869 9313 61486 78521 17 11 71 2 0
31 5 0 127817568 329836 3024708 0 0 45313 8085 75117 72291 33 24 42 1 0
zzz ***Wed Sep 26 22:46:32 EDT 2018
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
78 1 0 127798864 330116 3032880 0 0 655 262 65 173 14 10 76 1 0
24 5 0 127787808 330292 3037772 0 0 38497 7017 69303 66765 27 24 48 1 0
7 3 0 127801552 330428 3041988 0 0 47089 6874 68469 72912 25 20 54 1 0

 

Changes

 Kernel upgraded from UEK3 or RHCK to UEK4.

Cause

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In this Document
Symptoms
Changes
Cause
Solution
References


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