How to find which processes are taking all the memory?

I’m looking for somthing like top is to CPU usage. Is there a command line argument for top that does this? Currently, my memory is so full that even ‘man top’ fails with out of memory 🙂

Asked By: ripper234

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Once top starts, press F to switch to the sort field screen. Choose one of the fields listed by pressing the key listed on the left; you probably want N for MEM%

Answered By: Michael Mrozek

From inside top you can try the following:

  • Press SHIFT+f
  • Press the Letter corresponding to %MEM
  • Press ENTER

You might also try:

$ ps -eo pmem,pcpu,vsize,pid,cmd | sort -k 1 -nr | head -5

This will give the top 5 processes by memory usage.

Answered By: Steven D

If you have it installed I like htop once launching it you can press f6, down arrow (to MEM%), enter to sort by memory.

Answered By: xenoterracide

In Solaris the command you would need is:

prstat -a -s size

This will list all processes in order of descending process image size. Note that the latter is based on memory committed to the process by the OS, not its resident physical memory usage.

There are supposedly versions of “top” available for Solaris, but these are not part of the standard installation.

Answered By: Joel Hoff

One nice alternative to top is htop. Check it, it is much more user friendly than regular top.

Answered By: Klark

This command will identify the top memory consuming processes:

ps -A --sort -rss -o pid,pmem:40,cmd:500 | head -n 6 | tr -s " " ";z"
Answered By: user90191

You can try ps aux --sort -rss | head or ps aux | sort -nk +4 | tail

Answered By: David Okwii

It can be achieved in multiple ways,
My favourite one is:

The PS way:

  1. [arif@arif ~]$ ps -eo pid,cmd,%cpu,%mem --sort=-%mem

    Where,

    • -e: to select all process
    • -o: to apply to the output format
    • pid,cmd,%cpu,%mem: Output format in exact order. Here, pcpu and pmem can be used instead of %cpu and %mem.
    • But sadly (don’t know why) it doesn’t work on some machine (Oracle Linux) and some older machine. You can use the following similar alternatives.
  2. [arif@arif ~]$ ps aux --sort '-%mem' --cols 120 | head

    Where,

    • --cols 100: to specify column width of the output as sometimes cmd gets very long. This is not necessary if you don’t want curtailed commands with arguments.
    • aux: to see every process on the system using BSD syntax
  3. [arif@arif ~]$ ps -eo pid,cmd,%cpu,%mem --sort -rss

    Where,

    • -rss: resident set size, the non-swapped physical memory that a task has used
  4. [arif@arif ~]$ ps aux --sort -rss --cols 120

The top way:

[arif@arif ~]$ top -b -o +%MEM

Where,

  • -b: to use top as batch mode.
  • -o: to override sort fieldname followed by a fieldname %MEM

And you can always use head and/or tail to control the output.

Answered By: arif

Globally:
It’s always recommended to use a log analyser tool for logging history logs such as Splunk, ELK etc. So that using query language you can easily get the PIDs and its usage by CPU & memory.

AT SERVER/OS LEVEL:
From inside top you can try the following:

 Press SHIFT+M  ---> This will give you a process which takes more memory in descending order.

You might also try:

$ ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%mem | head -10

This will give the top 10 processes by memory usage.
Also you can use vmstat utility to find the RAM usage at same time not for history.

Answered By: Santosh Garole

This alias works nice for me in a bash shell:

alias mtop='{ echo "Mem% PID Binary"; ps -A --sort -rss -o pid,pmem:40,cmd:500 | tail -n +2 | head -n 10 | tr -s " " | sed -r "s/^s*([0-9]+) ([0-9.]+) ([a-zA-Z/]+).*$/2 1 3/"; } | column -t -s " "'

This will print out a neat list of processes sorted by memory consumption:

-=# mtop
Mem%  PID     Binary
22.9  528235  /opt/intellij
5.4   906569  /usr/share/elasticsearch/jdk/bin/java
3.7   544512  /usr/bin/node
2.2   986170  /usr/lib/firefox/firefox
1.9   795138  /usr/bin/node
1.1   795188  /usr/bin/node
1.0   747819  /usr/lib/jvm/java
0.9   599     /usr/bin/pipewire
0.7   414     /usr/lib/Xorg
0.7   544536  /usr/bin/node
Answered By: fasseg

On macOS, ps does not support the --sort option.

You can use the BSD-only -m flag to sort by "memory usage," which avoids piping all rows through sort. (The ps man page doesn’t specify exactly which "memory usage" metric is used.)

ps -m -aexo pmem,rss,vsize,pid,etime,user,args | head

Or, if you want sorting by CPU: you can use the BSD-only -r flag to sort by cpu usage.

ps -r -aexo pcpu,cputime,pid,etime,user,args | head
Answered By: Carl Walsh
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