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Oracle Linux: One CPU has 100% wait time on Server with QLogic FCoE card. (Doc ID 2618956.1)

Last updated on DECEMBER 17, 2019

Applies to:

Linux OS - Version Oracle Linux 7.6 with Unbreakable Enterprise Kernel [4.14.35] and later
Information in this document applies to any platform.

Symptoms

As per TOP command one CPU has 100% wait time:

top - 15:29:40 up  6:05,  1 user,  load average: 2.15, 2.06, 2.02
Tasks: 260 total,   1 running, 136 sleeping,   0 stopped,   0 zombie
%Cpu0  :  0.4 us,  0.0 sy,  0.0 ni, 99.6 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
%Cpu1  :  0.0 us,  0.0 sy,  0.0 ni,  0.0 id,100.0 wa,  0.0 hi,  0.0 si,  0.0 st  <<<<<<<<<<<<< 100.0 wa
%Cpu2  :  0.0 us,  0.0 sy,  0.0 ni,100.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
%Cpu3  :  0.0 us,  0.0 sy,  0.0 ni,100.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st

 

Also It can confirmed with MPSTAT command:

04:10:35 PM  CPU    %usr   %nice    %sys %iowait    %irq   %soft  %steal  %guest  %gnice   %idle
04:10:36 PM  all    0.00    0.00    0.25   24.94    0.00    0.00    0.00    0.00    0.00   74.81
04:10:36 PM    0    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00  100.00
04:10:36 PM    1    0.00    0.00    0.00  100.00    0.00    0.00    0.00    0.00    0.00    0.00  <<<<<<<<<<< 100.00 %iowait    
04:10:36 PM    2    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00  100.00
04:10:36 PM    3    0.00    0.00    0.99    0.00    0.00    0.00    0.00    0.00    0.00   99.01

Changes

Cause can be triggered for one of this reasons.

*) The core count was reduced.

*) There were installed a new kernel (UEK5 ).

*) A new QLogic FastLinQ FCoE card was installed.

Cause

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In this Document
Symptoms
Changes
Cause
Solution
References


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