08-E.10: CPU and Memory Troubleshooting

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EXAM OBJECTIVES COVERED
4.1 Given a scenario, analyze system properties and remediate accordingly.

CPU Issues

There are numerous potential issues that could affect or be caused by the CPU. These issues may include:

The CPU may be under-performing, because it may be overloaded
On multi-systems it is possible that one of the CPUs/Cores is not functioning properly
Due to the type and number of processes, one process may be consuming large amounts of CPU time, leaving inadequate processor time for other processes
The BIOS may not have virtualization or hyperthreading turned on
For some reason the CPU may be sitting idle too much of the time

This video discusses the /proc directory as well as some other system administration commands.

The /proc/cpuinfo File

/proc/cpuinfo is a short, read-only, plain text file that contains information about the CPUs (central processing units) on a computer.

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 23
model name      : Intel(R) Core(TM)2 Duo CPU     E8400  @ 3.00GHz
stepping        : 10
microcode       : 0xa0b
cpu MHz         : 2704.609
cache size      : 6144 KB
physical id     : 0
siblings        : 2
core id         : 0
cpu cores       : 2
apicid          : 0
initial apicid  : 0
fpu             : yes
fpu_exception   : yes
cpuid level     : 13
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs

Some of the more useful fields in the example output are:

processor – Provides each processor with an identifying number. If you have one processor it will display a 0. If you have more than one processor it will display all processor information separately counting the processors using zero notation.
cpu family – Authoritatively tells you the type of processor you have in the system. If your computer is an Intel-based system, simply place the number in front of “86” to determine the value. This is helpful to determine the type of architecture of an older system and is helpful in determining which compiled RPM package would best suit that system.
model name – Gives you the common name of the processor, including the project name.
cpu MHz – Shows the processor’s precise speed, in megahertz, to the thousandth decimal point.
cache size – Tells you the amount of level 2 memory cache available to the processor.
flags – Defines a number of different processor attributes, such as the presence of a floating-point unit (FPU) and the ability to process MMX instructions.

The uptime Command

The uptime command is used to find out how long the system is active (running). This command returns a set of values that involve the current time and the amount of time system is in running state, number of users currently logged into, and the load time for the past 1, 5, and 15 minutes respectively.

Syntax:

uptime [ OPTIONS ]

A couple of examples show the output in two different formats. There are additional formats based on other options, which can be found on the uptime man page.

pbmac@pbmac-server $ uptime
 16:53:01 up 5 days, 22:57,  1 user,  load average: 1.51, 1.35, 1.18
pbmac@pbmac-server $ uptime -p
up 5 days, 22 hours, 57 minutes

Adapted from:
"Linux | Uptime command with examples" by mistersubha, Geeks for Geeks is licensed under CC BY-SA 4.0