Cheatsheet: Difference between revisions

=== CPU ===

; CPU Info

* The number of processors shown by /proc/cpuinfo might not be the actual number of cores on the processor.

* For example a processor with 2 cores and hyperthreading would be reported as a processor with 4 cores.

* If there are 4 different core ids, this indicates that there are 4 actual cores.

# cat /proc/cpuinfo | grep 'core id'

; CPU Usage

; Top Command

CPU Section

us user cpu time % CPU time spent in user space

sy system cpu time % CPU time spent in kernel space

ni user nice cpu time % CPU time spent on low priority processes

id idle cpu time % CPU time spent idle

wa io wait cpu time % CPU time spent in wait (on disk)

hi hardware irq % CPU time spent servicing/handling hardware interrupts

si software irq % CPU time spent servicing/handling software interrupts

st steal time % CPU time stolen from a virtual machine

Main Section:

%MEM directly related to RES, percentage use of total physical memory by the process.

VIRT total memory that this process has access to shared memory, mapped pages, swapped out pages, etc.

RES total physical memory used shared or private that the process has access to.

SHR total physical shared memory that the process has access to.

RES is most close to the memory used by the process in memory, excluding what’s swapped out.

This includes the SHR (shared physical memory) which mean it could have been used by some other process as well.

;Obtain the PID with a utility:

pgrep -n python

pidof chrome - return all PIDs

pidof -s chrome - return only 1 PID

ps -C chrome -o pid= - C = CMD

du

df