Linux Command - top
The linux top command shows running processes and stats in real-time.
Start top:
top
Don’t show zombie or idle processes:
top -i
Sort by field:
top -o VIRT top -o RES top -o SHR top -o %CPU top -o %MEM top -o COMMAND
Only processes with these pids:
top -p 1257,1258
top -p $( pgrep -d ‘,’ gnome )
Individual threads of a process:
top -Hp 1257
Only processes owned by this user:
top -u user1
Batch mode, repeat once:
top -b -n 1
===================================================================== top from procps-ng 4.0.2
h ? q ctrl-c
arrow keys to scroll
memory: physical, swap, virtual
4096 - typical page
memory quadrant diagram (private/shared - Anonymous / File-backed)
Private | Shared
1 | 2
Anonymous . stack |
. malloc() |
. brk()/sbrk() | . POSIX shm*
. mmap(PRIVATE, ANON) | . mmap(SHARED, ANON)
-----------------------+----------------------
. mmap(PRIVATE, fd) | . mmap(SHARED, fd)
File-backed . pgms/shared libs |
3 | 4
%MEM - simply RES divided by total physical memory
CODE - the `pgms' portion of quadrant 3
DATA - the entire quadrant 1 portion of VIRT plus all
explicit mmap file-backed pages of quadrant 3
RES - anything occupying physical memory which, beginning with
Linux-4.5, is the sum of the following three fields:
RSan - quadrant 1 pages, which include any
former quadrant 3 pages if modified
RSfd - quadrant 3 and quadrant 4 pages
RSsh - quadrant 2 pages
RSlk - subset of RES which cannot be swapped out (any quadrant)
SHR - subset of RES (excludes 1, includes all 2 & 4, some 3)
SWAP - potentially any quadrant except 4
USED - simply the sum of RES and SWAP
VIRT - everything in-use and/or reserved (all quadrants)
-b batch mode, doesn’t accept input, runs until ‘-n’ iteration limit or killed -n max iterations before ending
-d delay in seconds for refresh -E memory scale for summary area -e memory scale for task area
k - kibibytes
m - mebibytes
g - gibibytes
t - tebibytes
p - pebibytes
e - exbibytes
-H show individual threads, also threads instead of tasks at top -h help
-O print list of fields
-o select field to sort by, +/- to specify sort order + high to low - low to high
-p monitor comma separated list of pids
-s secure mode
-U username or user ID ( real, effective, saved, filesystem ), use ! to negate -u username or user ID ( effective ), use ! to negate
system load avg over the last 1, 5 and 15 minutes
us : time running un-niced user processes
sy : time running kernel processes
ni : time running niced user processes
id : time spent in the kernel idle handler
wa : time waiting for I/O completion
hi : time spent servicing hardware interrupts
si : time spent servicing software interrupts
st : time stolen from this vm by the hypervisor
t switch mode, can show user, system, total percent, graph
a b c d
%Cpu(s): 75.0/25.0 100[ ... ]
%CPU – CPU Usage can be over 100 if multi threaded
Irix mode - ....
Solaris mode - CPU usage divided by number of CPUs
shows usage for children when inforest mode
I Irix mode on / off
%CUC – CPU Utilization ( devided by running time as percentage ), include reaped procs %CUU – CPU Utilization ( devided by running time as percentage ) %MEM – Memory Usage (RES)
AGID – Autogroup Identifier The autogroup identifier associated with a process. This feature operates in conjunction with the CFS scheduler to improve interactive desktop performance.
When /proc/sys/kernel/sched_autogroup_enabled is set, a new autogroup is created
with each new session (see SID). All subsequently forked processes in that session
inherit membership in this autogroup. The kernel then attempts to equalize
distribution of CPU cycles across such groups. Thus, an autogroup with many CPU
intensive processes (e.g make -j) will not dominate an autogroup with only one or
two processes.
When -1 is displayed it means this information is not available.
AGNI – Autogroup Nice Value ( for all procs in group ) CGNAME – Control Group Name CGROUPS – Control Groups CODE – Code Size (KiB) - mem dedicated to executable code ( Text Resident Set size or TRS ) COMMAND – Command Name or Command Line ( use ‘c’ to toggle between command line and name ) DATA – Data + Stack Size (KiB) ( Data Resident Set or DRS ) always virtual, might not be physical ELAPSED – Elapsed Running Time ENVIRON – Environment variables EXE – Executable Path Flags – Task Flags ( scheduling flags ) GID – Group Id GROUP – Group Name LOGID – Login User Id LXC – Lxc Container Name NI – Nice Value NU – Last known NUMA node OOMa – Out of Memory Adjustment Factor ( added to OOMs )( -1000 to +1000, determines which task to kill on OOM) OOMs – Out of Memory Score ( 0 to +1000, 0 never kill, 1000 always kill) P – Last used CPU (SMP) PGRP – Process Group Id PID – Process Id PPID – Parent Process Id PR – Priority ( scheduling priority, rt is real time)
PSS – Proportional Resident Memory, smaps (KiB) PSan – Proportional Anonymous Memory, smaps (KiB) PSfd – Proportional File Memory, smaps (KiB) PSsh – Proportional Shmem Memory, smaps (KiB)
RES – Resident Memory Size (KiB) -( non-swapped physical memory ) RSS – Resident Memory, smaps (KiB) RSan – Resident Anonymous Memory Size (KiB) RSfd – Resident File-Backed Memory Size (KiB) RSlk – Resident Locked Memory Size (KiB)
RSsh – Resident Shared Memory Size (KiB) RUID – Real User Id RUSER – Real User Name
S – Process Status The status of the task which can be one of: D = uninterruptible sleep I = idle R = running S = sleeping T = stopped by job control signal t = stopped by debugger during trace Z = zombie
SHR – Shared Memory Size (KiB) - part of RES, may be used by other procs SID – Session Id STARTED – Start Time Interval “length of time since system boot when a process started” SUID – Saved User Id SUPGIDS – Supplementary Group IDs SUPGRPS – Supplementary Group Names SUSER – Saved User Name
SWAP – Swapped Size (KiB) - mem that was swapped out after physical mem is overcommitted
TGID – Thread Group Id
TIME – CPU Time - total CPU time used - ‘S’ to toggle cumulative mode and show usage for dead children TIME+ – CPU Time, hundredths
TPGID – Tty Process Group Id
TTY – Controlling Tty
UID – User Id
USED – Memory in Use (KiB) - physical and swap usage ( RES + SWAP )
USER – User Name - effective user name of task owner
USS – Unique Set Size - non swapped physical mem usage not shared with other procs
VIRT – Virtual Memory Size (KiB)
WCHAN – Sleeping in Function - kernel function name that task is sleeping in
ioR – I/O Bytes Read ioRop – I/O Read Operations ( syscalls, might n ot have actual physical I/O)
ioW – I/O Bytes Written ioWop – I/O Write Operations ( syscalls, might n ot have actual physical I/O)
nDRT – Dirty Pages Count - pages not written to aux storage - can’t be swapped out yet ) nMaj – Major Page Fault Count - attepmt to read virt mem that isn’t there and need to use aux storage nMin – Minor Page Fault count - attepmt to read virt mem that isn’t there and DOESN’T need to use aux storage vMj – Major Page Fault Count Delta - Major Page Faults since last update vMn – Minor Page Fault Count Delta - Minor Page Faults since last update
nTH – Number of Threads
nsCGROUP – CGROUP namespace nsIPC – IPC namespace nsMNT – MNT namespace nsNET – NET namespace nsPID – PID namespace nsTIME – TIME namespace nsUSER – USER namespace nsUTS – UTS namespace
========
f manage fields - show screen and sort field
up,down, pgup, pgdn, home, end - navigate
right arrow - select field for repositioning left arrow / enter - commit position d / space - toggle display status s - set selected field as sort field a/w - cycle through windows q/esc - quit ( exits to selected window )
g
Secure mode will dissallow doing things like killing, renicing, etc. It is also enforced for root.
GLOBAL Commands
enter / space - refresh now
q quit
? / h get help
= exit display limits - basically remove all filtering and stuff
0 Zero-Suppress toggle - don’t show zero for some fields
A Alternate-Display-Mode toggle
B :Bold-Disable/Enable toggle
d / s Change-Delay-Time-interval - can be positive, fractional, or zero
E Enforce-Summary-Memory-Scale in Summary Area - cycle between KiB - EiB
e Enforce-Task-Memory-Scale in Task Area - cycle between KiB - EiB
g Choose-Another-Window/Field-Group - select window, prompts for number 1-4
H :Threads-mode toggle - show threads instead of summation
I :Irix/Solaris-Mode toggle
k :Kill-a-task - prompted for PID and signal
r :Renice-a-Task - prompted for PID and nice value
W :Write-the-Configuration-File - save settings in config file
X :Extra-Fixed-Width - adjust width for some columns
Y :Inspect-Other-Output - prompt for PID, show info on other screen
needs configuration in config file
key function
= alternate status-line, file or pipeline
/ find, equivalent to `L' locate
n find next, equivalent to `&' locate next
<Space> scroll down, equivalent to <PgDn>
b scroll up, equivalent to <PgUp>
g first line, equivalent to <Home>
G last line, equivalent to <End>
Z :Change-Color-Mapping - prompts for keys to change collors
^G :Display-Control-Groups (Ctrl key + g') ( for first proc listed )
^K :Display-Cmdline (Ctrl key + k’) ( for first proc listed )
^N :Display-Environment (Ctrl key + n') ( for first proc listed )
^P :Display-Namesspaces (Ctrl key + p’) ( for first proc listed )
^U :Display-Supplementary-Groups (Ctrl key + u') ( for first proc listed )
^L :Logged-Messages (Ctrl key + l’) - show recetn messges
^R :Renice-an-Autogroup (Ctrl key + `r’)
SUMMARY AREA Commands
C :Show-scroll-coordinates toggle l :Load-Average/Uptime toggle m :Memory/Swap-Usage toggle t :Task/Cpu-States toggle - summary lines 1 :Single/Separate-Cpu-States toggle 2 :NUMA-Nodes/Cpu-Summary toggle 3 :Expand-NUMA-Node 4 :Display-Multiple-Elements-Adjacent toggle 5 :Display-P-Cores-and-E-Cores toggle ! :Combine-Cpus-Mode toggle
1-! commands may affect t command
TASK AREA Commands
J :Justify-Numeric-Columns toggle j :Justify-Character-Columns toggle b :Bold/Reverse toggle x :Column-Highlight toggle - for sort field - column turns bold - if color mode (‘z’) col also is colored y :Row-Highlight toggle - running tasks turn bold, if color mode (‘z’) col also is colored z :Color/Monochrome toggle - conflicts with colors picked with “Z” ( capital )
c :Command-Line/Program-Name toggle F :Maintain-Parent-Focus toggle - in forest mode, select top task and pin it to the top basically f :Fields-Management - …. ….. O | o :Other-Filtering - setup task filtering ….. more info ….
S :Cumulative-Time-Mode toggle - count CPU time of dead children or not
| U | u :Show-Specific-User-Only - prompt to filter by user: ex: ‘user1’ or ‘!user1’ |
V :Forest-View-Mode toggle - order procs by parent v :Hide/Show-Children toggle - show / hide children of top most ( selected ) proc
^E :Scale-CPU-Time-fields (Ctrl key + `e’)
i :Idle-Process toggle - show / don’t show idle tasks n | # :Set-Maximum-Tasks
Sort keys from old top: () ????? )
command sorted-field supported
A start time (non-display) No
M %MEM Yes
N PID Yes
P %CPU Yes
T TIME+ Yes
might need colum highlighted with ‘x’ command before you can change col to sort on
< :Move-Sort-Field-Left
:Move-Sort-Field-Right
R :Reverse/Normal-Sort-Field toggle
full-screen mode - 1 window at a time alternate-display mod - all windows at once, can disable some or all, current window shown on summary line
1-4 windows exist
Alternate display mode
A Alternate-Display-Mode toggle - switch between full screen and alternate display mode
- (dash) hide current window _ (underscore) inverse which windows are hidden or hide all_
= force current window task display visible and clear all filters resetting window
- same but for all windows a next window w previous window