pcp-htop - interactive process viewer
htop [
-dCFhpustvH]
pcp htop [
-dCFhpustvH] [
--host/-h host]
htop is a cross-platform ncurses-based process viewer.
It is similar to
top, but allows you to scroll vertically and
horizontally, and interact using a pointing device (mouse). You can observe
all processes running on the system, along with their command line arguments,
as well as view them in a tree format, select multiple processes and act on
them all at once.
Tasks related to processes (killing, renicing) can be done without entering
their PIDs.
pcp-htop is a version of
htop built using the Performance Co-Pilot
(PCP) Metrics API (see
PCPIntro(1),
PMAPI(3)), allowing to
extend
htop to display values from arbitrary metrics. See the section
below titled
CONFIG FILES for further details.
Mandatory arguments to long options are mandatory for short options too.
- -d --delay=DELAY
- Delay between updates, in tenths of a second. If the delay
value is less than 1, it is increased to 1, i.e. 1/10 second. If the delay
value is greater than 100, it is decreased to 100, i.e. 10 seconds.
- -C --no-color --no-colour
- Start htop in monochrome mode
- -F --filter=FILTER
- Filter processes by terms matching the commands. The terms
are matched case-insensitive and as fixed strings (not regexs). You can
separate multiple terms with "|".
- -h --help
- Display a help message and exit
- -p --pid=PID,PID...
- Show only the given PIDs
- -s --sort-key COLUMN
- Sort by this column (use --sort-key help for a column
list). This will force a list view unless you specify -t at the same
time.
- -u --user=USERNAME|UID
- Show only the processes of a given user
- -U --no-unicode
- Do not use unicode but ASCII characters for graph
meters
- -M --no-mouse
- Disable support of mouse control
- --readonly
- Disable all system and process changing features
- -V --version
- Output version information and exit
- -t --tree
- Show processes in tree view. This can be used to force a
tree view when requesting a sort order with -s.
- -H --highlight-changes=DELAY
- Highlight new and old processes
- --drop-capabilities[=off|basic|strict]
- Linux only; requires libcap support.
Drop unneeded Linux capabilities. In strict mode features like killing,
changing process priorities, and reading process delay accounting
information will not work, due to less capabilities held.
The following commands are supported while in
htop:
- Tab, Shift-Tab
- Select the next / the previous screen tab to display. You
can enable showing the screen tab names in the Setup screen (F2).
- Up, Alt-k
- Select (highlight) the previous process in the process
list. Scroll the list if necessary.
- Down, Alt-j
- Select (highlight) the next process in the process list.
Scroll the list if necessary.
- Left, Alt-h
- Scroll the process list left.
- Right, Alt-l
- Scroll the process list right.
- PgUp, PgDn
- Scroll the process list up or down one window.
- Home
- Scroll to the top of the process list and select the first
process.
- End
- Scroll to the bottom of the process list and select the
last process.
- Ctrl-A, ^
- Scroll left to the beginning of the process entry (i.e.
beginning of line).
- Ctrl-E, $
- Scroll right to the end of the process entry (i.e. end of
line).
- Space
- Tag or untag a process. Commands that can operate on
multiple processes, like "kill", will then apply over the list
of tagged processes, instead of the currently highlighted one.
- c
- Tag the current process and its children. Commands that can
operate on multiple processes, like "kill", will then apply over
the list of tagged processes, instead of the currently highlighted
one.
- U
- Untag all processes (remove all tags added with the Space
or c keys).
- s
- Trace process system calls: if strace(1) is installed,
pressing this key will attach it to the currently selected process,
presenting a live update of system calls issued by the process.
- l
- Display open files for a process: if lsof(1) is installed,
pressing this key will display the list of file descriptors opened by the
process.
- w
- Display the command line of the selected process in a
separate screen, wrapped onto multiple lines as needed.
- x
- Display the active file locks of the selected process in a
separate screen.
- F1, h, ?
- Go to the help screen
- F2, S
- Go to the setup screen, where you can configure the meters
displayed at the top of the screen, set various display options, choose
among color schemes, and select which columns are displayed, in which
order.
- F3, /
- Incrementally search the command lines of all the displayed
processes. The currently selected (highlighted) command will update as you
type. While in search mode, pressing F3 will cycle through matching
occurrences. Pressing Shift-F3 will cycle backwards.
Alternatively the search can be started by simply typing the command you are
looking for, although for the first character normal key bindings take
precedence.
- F4, \
- Incremental process filtering: type in part of a process
command line and only processes whose names match will be shown. To cancel
filtering, enter the Filter option again and press Esc. The matching is
done case-insensitive. Terms are fixed strings (no regex). You can
separate multiple terms with "|".
- F5, t
- Tree view: organize processes by parenthood, and layout the
relations between them as a tree. Toggling the key will switch between
tree and your previously selected sort view. Selecting a sort view will
exit tree view.
- F6, <, >
- Selects a field for sorting, also accessible through <
and >. The current sort field is indicated by a highlight in the
header.
- F7, ]
- Increase the selected process's priority (subtract from
'nice' value). This can only be done by the superuser.
- F8, [
- Decrease the selected process's priority (add to 'nice'
value)
- Shift-F7, }
- Increase the selected process's autogroup priority
(subtract from autogroup 'nice' value). This can only be done by the
superuser.
- Shift-F8, {
- Decrease the selected process's autogroup priority (add to
autogroup 'nice' value)
- F9, k
- "Kill" process: sends a signal which is selected
in a menu, to one or a group of processes. If processes were tagged, sends
the signal to all tagged processes. If none is tagged, sends to the
currently selected process.
- F10, q
- Quit
- I
- Invert the sort order: if sort order is increasing, switch
to decreasing, and vice-versa.
- +, -, *
- When in tree view mode, expand or collapse subtree. When a
subtree is collapsed a "+" sign shows to the left of the process
name. Pressing "*" will expand or collapse all children of PIDs
without parents, so typically PID 1 (init) and PID 2 (kthreadd on Linux,
if kernel threads are shown).
- a (on multiprocessor machines)
- Set CPU affinity: mark which CPUs a process is allowed to
use.
- u
- Show only processes owned by a specified user.
- N
- Sort by PID.
- M
- Sort by memory usage (top compatibility key).
- P
- Sort by processor usage (top compatibility key).
- T
- Sort by time (top compatibility key).
- F
- "Follow" process: if the sort order causes the
currently selected process to move in the list, make the selection bar
follow it. This is useful for monitoring a process: this way, you can keep
a process always visible on screen. When a movement key is used,
"follow" loses effect.
- K
- Hide kernel threads: prevent the threads belonging the
kernel to be displayed in the process list. (This is a toggle key.)
- H
- Hide user threads: on systems that represent them
differently than ordinary processes (such as recent NPTL-based systems),
this can hide threads from userspace processes in the process list. (This
is a toggle key.)
- p
- Show full paths to running programs, where applicable.
(This is a toggle key.)
- Z
- Pause/resume process updates.
- m
- Merge exe, comm and cmdline, where applicable. (This is a
toggle key.)
- Ctrl-L
- Refresh: redraw screen and recalculate values.
- Numbers
- PID search: type in process ID and the selection highlight
will be moved to it.
The following columns can display data about each process. A value of '-' in all
the rows indicates that a column is unsupported on your system, or currently
unimplemented in
htop. The names below are the ones used in the
"Available Columns" section of the setup screen. If a different name
is shown in
htop's main screen, it is shown below in parenthesis.
- Command
- The full command line of the process (i.e. program name and
arguments).
If the option 'Merge exe, comm and cmdline in Command' (toggled by the 'm'
key) is active, the executable path (/proc/[pid]/exe) and the command name
(/proc/[pid]/comm) are also shown merged with the command line, if
available.
The program basename is highlighted if set in the configuration. Additional
highlighting can be configured for stale executables (cf. EXE column
below).
- COMM
- The command name of the process obtained from
/proc/[pid]/comm, if readable.
Requires Linux kernel 2.6.33 or newer.
- EXE
- The abbreviated basename of the executable of the process,
obtained from /proc/[pid]/exe, if readable. htop is able to read this file
on linux for ALL the processes only if it has the capability
CAP_SYS_PTRACE or root privileges.
The basename is marked in red if the executable used to run the process has
been replaced or deleted on disk since the process started. The
information is obtained by processing the contents of /proc/[pid]/exe.
Furthermore the basename is marked in yellow if any library is reported as
having been replaced or deleted on disk since it was last loaded. The
information is obtained by processing the contents of /proc/[pid]/maps.
When deciding the color the replacement of the main executable always takes
precedence over replacement of any other library. If only the memory map
indicates a replacement of the main executable, this will show as if any
other library had been replaced or deleted.
This additional color markup can be configured in the "Display
Options" section of the setup screen.
Displaying EXE requires CAP_SYS_PTRACE and PTRACE_MODE_READ_FSCRED.
- PID
- The process ID.
- STATE (S)
- The state of the process:
S for sleeping
I for idle (longer inactivity than sleeping on platforms that
distinguish)
R for running
D for disk sleep (uninterruptible)
Z for zombie (waiting for parent to read its exit status)
T for traced or suspended (e.g by SIGTSTP)
W for paging
- PPID
- The parent process ID.
- PGRP
- The process's group ID.
- SESSION (SID)
- The process's session ID.
- TTY
- The controlling terminal of the process.
- TPGID
- The process ID of the foreground process group of the
controlling terminal.
- MINFLT
- The number of page faults happening in the main
memory.
- CMINFLT
- The number of minor faults for the process's waited-for
children (see MINFLT above).
- MAJFLT
- The number of page faults happening out of the main
memory.
- CMAJFLT
- The number of major faults for the process's waited-for
children (see MAJFLT above).
- UTIME (UTIME+)
- The user CPU time, which is the amount of time the process
has spent executing on the CPU in user mode (i.e. everything but system
calls), measured in clock ticks.
- STIME (STIME+)
- The system CPU time, which is the amount of time the kernel
has spent executing system calls on behalf of the process, measured in
clock ticks.
- CUTIME (CUTIME+)
- The children's user CPU time, which is the amount of time
the process's waited-for children have spent executing in user mode (see
UTIME above).
- CSTIME (CSTIME+)
- The children's system CPU time, which is the amount of time
the kernel has spent executing system calls on behalf of all the process's
waited-for children (see STIME above).
- PRIORITY (PRI)
- The kernel's internal priority for the process, usually
just its nice value plus twenty. Different for real-time processes.
- NICE (NI)
- The nice value of a process, from 19 (low priority) to -20
(high priority). A high value means the process is being nice, letting
others have a higher relative priority. The usual OS permission
restrictions for adjusting priority apply.
- STARTTIME (START)
- The time the process was started.
- PROCESSOR (CPU)
- The ID of the CPU the process last executed on.
- M_VIRT (VIRT)
- The size of the virtual memory of the process.
- M_RESIDENT (RES)
- The resident set size (text + data + stack) of the process
(i.e. the size of the process's used physical memory).
- M_SHARE (SHR)
- The size of the process's shared pages.
- M_TRS (CODE)
- The text resident set size of the process (i.e. the size of
the process's executable instructions).
- M_DRS (DATA)
- The data resident set size (data + stack) of the process
(i.e. the size of anything except the process's executable
instructions).
- M_LRS (LIB)
- The library size of the process.
- M_SWAP (SWAP)
- The size of the process's swapped pages.
- M_PSS (PSS)
- The proportional set size, same as M_RESIDENT but each page
is divided by the number of processes sharing it.
- M_M_PSSWP (PSSWP)
- The proportional swap share of this mapping, unlike M_SWAP
this does not take into account swapped out page of underlying shmem
objects.
- ST_UID (UID)
- The user ID of the process owner.
- PERCENT_CPU (CPU%)
- The percentage of the CPU time that the process is
currently using. This is the default way to represent CPU usage in Linux.
Each process can consume up to 100% which means the full capacity of the
core it is running on. This is sometimes called "Irix mode" e.g.
in top(1).
- PERCENT_NORM_CPU (NCPU%)
- The percentage of the CPU time that the process is
currently using normalized by CPU count. This is sometimes called
"Solaris mode" e.g. in top(1).
- PERCENT_MEM (MEM%)
- The percentage of memory the process is currently using
(based on the process's resident memory size, see M_RESIDENT above).
- USER
- The username of the process owner, or the user ID if the
name can't be determined.
- TIME (TIME+)
- The time, measured in clock ticks that the process has
spent in user and system time (see UTIME, STIME above).
- NLWP
- The number of Light-Weight Processes (=threads) in the
process.
- TGID
- The thread group ID.
- CTID
- OpenVZ container ID, a.k.a virtual environment ID.
- VPID
- OpenVZ process ID.
- VXID
- VServer process ID.
- RCHAR (RD_CHAR)
- The number of bytes the process has read.
- WCHAR (WR_CHAR)
- The number of bytes the process has written.
- SYSCR (RD_SYSC)
- The number of read(2) syscalls for the process.
- SYSCW (WR_SYSC)
- The number of write(2) syscalls for the process.
- RBYTES (IO_RBYTES)
- Bytes of read(2) I/O for the process.
- WBYTES (IO_WBYTES)
- Bytes of write(2) I/O for the process.
- CNCLWB (IO_CANCEL)
- Bytes of cancelled write(2) I/O.
- IO_READ_RATE (DISK READ)
- The I/O rate of read(2) in bytes per second, for the
process.
- IO_WRITE_RATE (DISK WRITE)
- The I/O rate of write(2) in bytes per second, for the
process.
- IO_RATE (DISK R/W)
- The I/O rate, IO_READ_RATE + IO_WRITE_RATE (see
above).
- CGROUP
- Which cgroup the process is in. For a shortened view see
the CCGROUP column below.
- CCGROUP
- Shortened view of the cgroup name that the process is in.
This performs some pattern-based replacements to shorten the displayed
string and thus condense the information.
/*.slice is shortened to /[*] (exceptions below)
/system.slice is shortened to /[S]
/user.slice is shortened to /[U]
/user-*.slice is shortened to /[U:*] (directly preceding
/[U] before dropped)
/machine.slice is shortened to /[M]
/machine-*.scope is shortened to /[SNC:*] (SNC: systemd
nspawn container), uppercase for the monitor
/lxc.monitor.* is shortened to /[LXC:*]
/lxc.payload.* is shortened to /[lxc:*]
/*.scope is shortened to /!*
/*.service is shortened to /* (suffix removed)
Encountered escape sequences (e.g. from systemd) inside the cgroup name are
not decoded.
- OOM
- OOM killer score.
- CTXT
- Incremental sum of voluntary and nonvoluntary context
switches.
- IO_PRIORITY (IO)
- The I/O scheduling class followed by the priority if the
class supports it:
R for Realtime
B for Best-effort
id for Idle
- PERCENT_CPU_DELAY (CPUD%)
- The percentage of time spent waiting for a CPU (while
runnable). Requires CAP_NET_ADMIN.
- PERCENT_IO_DELAY (IOD%)
- The percentage of time spent waiting for the completion of
synchronous block I/O. Requires CAP_NET_ADMIN.
- PERCENT_SWAP_DELAY (SWAPD%)
- The percentage of time spent swapping in pages. Requires
CAP_NET_ADMIN.
- AGRP
- The autogroup identifier for the process. Requires Linux
CFS to be enabled.
- ANI
- The autogroup nice value for the process autogroup.
Requires Linux CFS to be enabled.
- All other flags
- Currently unsupported (always displays '-').
While
htop depends on most of the libraries it uses at build time there
are two noteworthy exceptions to this rule. These exceptions both relate to
data displayed in meters displayed in the header of
htop and were
intentionally created as optional runtime dependencies instead. These
exceptions are described below:
- libsystemd
- The bindings for libsystemd are used in the SystemD meter
to determine the number of active services and the overall system state.
Looking for the functions to determine these information at runtime allows
for builds to support these meters without forcing the package manager to
install these libraries on systems that otherwise don't use systemd.
Summary: no build time dependency, optional runtime dependency on
libsystemd via dynamic loading, with systemctl(1)
fallback.
- libsensors
- The bindings for libsensors are used for the CPU
temperature readings in the CPU usage meters if displaying the temperature
is enabled through the setup screen. In order for htop to show
these temperatures correctly though, a proper configuration of libsensors
through its usual configuration files is assumed and that all CPU cores
correspond to temperature sensors from the coretemp driver with
core 0 corresponding to a sensor labelled "Core 0". The package
temperature may be given as "Package id 0". If missing it is
inferred as the maximum value from the available per-core readings.
Summary: build time dependency on libsensors(3) C header files,
optional runtime dependency on libsensors(3) via dynamic
loading.
By default
htop reads its configuration from the XDG-compliant path
~/.config/htop/htoprc. The configuration file is overwritten by
htop's in-program Setup configuration, so it should not be hand-edited.
If no user configuration exists
htop tries to read the system-wide
configuration from
/etc/pcp/htoprc and as a last resort, falls back to
its hard coded defaults.
You may override the location of the configuration file using the $HTOPRC
environment variable (so you can have multiple configurations for different
machines that share the same home directory, for example).
The
pcp-htop utility makes use of
htoprc in exactly the same way.
In addition, it supports additional configuration files allowing new meters
and columns to be added to the display via the usual Setup function, which
will display additional Available Meters and Available Column entries for each
runtime configured meter or column.
These
pcp-htop configuration files are read once at startup. The format
of these files is described in detail in the
pcp-htop(5) manual page.
This functionality makes available many thousands of Performance Co-Pilot
metrics for display by
pcp-htop, as well as the ability to display
custom metrics added at individual sites. Applications and services
instrumented using the OpenMetrics format
https://openmetrics.io can
also be displayed by
pcp-htop if the
pmdaopenmetrics(1)
component is configured.
Memory sizes in
htop are displayed in a human-readable form. Sizes are
printed in powers of 1024. (e.g., 1023M = 1072693248 Bytes)
The decision to use this convention was made in order to conserve screen space
and make memory size representations consistent throughout
htop.
proc(5),
top(1),
free(1),
ps(1),
uptime(1)
and
limits.conf(5).
pmdaopenmetrics(1),
PCPIntro(1),
PMAPI(3), and
pcp-htop(5).
htop was originally developed by Hisham Muhammad. Nowadays it is
maintained by the community at <
[email protected]>.
pcp-htop is maintained as a collaboration between the
<
[email protected]> and <
[email protected]> communities, and forms part
of the Performance Co-Pilot suite of tools.
Copyright © 2004-2019 Hisham Muhammad.
Copyright © 2020-2023 htop dev team.
License GPLv2+: GNU General Public License version 2 or, at your option, any
later version.
This is free software: you are free to change and redistribute it. There is NO
WARRANTY, to the extent permitted by law.