How to monitor CPU or memory usage on a per-user basis

How to monitor CPU or memory usage on a per-user basis

https://access.redhat.com/solutions/239483

 

 SOLUTION 已验证 - 已更新 2015年九月15日19:08 - 

English 

环境

• Red Hat Enterprise Linux

问题

• Need a way to determine what percentage of the CPUs and memory (RAM) each user is utilizing. Ideally, would like to have a command that printed something like the following.

  Raw

  user1 13% of total cpu usage, 25% of total ram
  user2 22% of total cpu usage, 2% of total ram
  

• Is there any command to fetch proportional set size of memory per user basis?

决议

This can be accomplished using top or ps.

Why to use ps, and why not to

• ps is perfect for quickly getting info on RAM or CPU usage, but it pales in comparison to top for real-time CPU usage stats. For further explanation, see the article: CPU usage reporting in ps versus top

• That said, here's how one could get the requested info from the ps command with a one-liner:

  Raw

  ps axo user,pcpu,pmem,rss --no-heading | awk '{pCPU[$1]+=$2; pMEM[$1]+=$3; sRSS[$1]+=$4} END {for (user in pCPU) if (pCPU[user]>0 || sRSS[user]>10240) printf "%s:@%.1f%% of total CPU,@%.1f%% of total MEM@(%.2f GiB used)\n", user, pCPU[user], pMEM[user], sRSS[user]/1024/1024}' | column -ts@ | sort -rnk2
  

• Example output:

  Raw

  qemu:    118.0% of total CPU,  0.4% of total MEM   (0.04 GiB used)
  rsaw:    7.7% of total CPU,    22.0% of total MEM  (1.87 GiB used)
  root:    1.2% of total CPU,    1.3% of total MEM   (0.23 GiB used)
  

How to use top, for better CPU-usage inspection

• The following steps walk through creating a simple top-wrapper script. By default the script and its config file will be called utop, but this is arbitrary and configurable -- simply change the initial name=utop line as desired.

1. First, a custom top config file needs to be created to make it possible to properly-customize top's options. (Why?1)
   Copy and paste the following into a root shell to create the necessary .toprc file inside a new directory in /usr/local/etc/.

   Raw

   name=utop
   mkdir -p /usr/local/etc/$name
   cat >/usr/local/etc/$name/.toprc <<\EOF
   RCfile for "top with windows"       # shameless braggin'
   Id:a, Mode_altscr=0, Mode_irixps=0, Delay_time=3.000, Curwin=0
   Def fieldscur=aEhioqtwKNmbcdfgjplrsuvyzx
       winflags=34105, sortindx=10, maxtasks=0
       summclr=1, msgsclr=1, headclr=3, taskclr=1
   Job fieldscur=ABcefgjlrstuvyzMKNHIWOPQDX
       winflags=62777, sortindx=0, maxtasks=0
       summclr=6, msgsclr=6, headclr=7, taskclr=6
   Mem fieldscur=ANOPQRSTUVbcdefgjlmyzWHIKX
       winflags=62777, sortindx=13, maxtasks=0
       summclr=5, msgsclr=5, headclr=4, taskclr=5
   Usr fieldscur=ABDECGfhijlopqrstuvyzMKNWX
       winflags=62777, sortindx=4, maxtasks=0
       summclr=3, msgsclr=3, headclr=2, taskclr=3
   EOF
   echo "$name's .toprc config file is in this dir" >/usr/local/etc/$name/README
   

2. Do the same (copy & paste) for the following to create the script in /usr/local/bin/.

   Raw

   cat >/usr/local/bin/$name <<EOF
   #!/bin/bash
   HOME=/usr/local/etc/$name top -bn1 | awk '
     NR>2 && NF>0 { pCPU[\$1]+=\$2 ; pMEM[\$1]+=\$3 }
     END {
       for (user in pCPU) if (pCPU[user]>0.5 || pMEM[user]>0.5)
         printf "%s:@%.1f%% of total CPU,@%.1f%% of total MEM\\n", user, pCPU[user], pMEM[user]
     }
   ' | column -ts@ | sort -rnk2
   EOF
   chmod +x /usr/local/bin/$name
   

3. Finally, run utop (or whatever name was chosen) as any user. Example output:

   Raw

   $ utop
   rsaw:   24.0% of total CPU,  68.7% of total MEM
   root:   2.0% of total CPU,   4.0% of total MEM
   lex:    1.1% of total CPU,   20.2% of total MEM
   named:  0.6% of total CPU,   0.4% of total MEM
   

• Customization notes:

  • The way the awk command is crafted, it will only print info for users that are using greater than 0.5% of total CPU or memory (i.e., half of 1%). To change this, look for the if (pCPU[user]>0.5 || pMEM[user]>0.5) code. Each number represents a percentage and so could either be changed to a different number (like 0 or 1 or 5 or 20) or the whole code block could be removed completely to see info on all users' processes.

  • If the extra decimal point of precision is not desired, change the 1 to a 0 in each occurrence of %.1f.

---

1. Why is a separate top config file necessary? Creating a special directory just to contain a top config file might seem excessive, but this will allow toggling top options, both for increased performance and for enhanced display, i.e.: toggling Irix/Solaris mode so that the number of logical processors are taken into account in the calculation of the cpu usage %. Example: If a system has four logical processors and a user's program is pegging a processor at 100%, top's default "Solaris" mode will report 100% cpu utilization for that program, whereas "Irix" mode would report 25%. In summary: Without changing top to use Irix mode, the cpu usage of different users can be compared; however, users' cpu usage cannot be easily judged against what is available on the system (unless the admin behind the keyboard gives extra thought to the number of logical processors present). ↩