SLABTOP

Section: User Commands (1)
Updated: 202-1-26
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NAME

slabtop - display kernel slab cache information in real time  

SYNOPSIS

slabtop [option ...]  

DESCRIPTION

slabtop displays detailed kernel slab cache information in real time. It displays a listing of the top caches sorted by one of the listed sort criteria. It also displays a statistics header filled with slab layer information.  

OPTIONS

Normal invocation of slabtop does not require any options. The behavior, however, can be fin-tuned by specifying one or more of the following flags:

-d, --delay=N

Refresh the display every n in seconds. By default, slabtop refreshes the display every three seconds. To exit the program, hit q. This cannot be combined with the -o option.

-s, --sort=S

Sort by S, where S is one of the sort criteria.

-o, --once

Display the output once and then exit.

--human

Show slab sizes automatically scaled to shortest three digit unit and display the units of print out. Following units are used.

  B = bytes
  Ki = kibibyte
  Mi = mebibyte
  Gi = gibibyte
  Ti = tebibyte
  Pi = pebibyte

If this flag is not used, the slab sizes will be shown in KiB.

-V, --version

Display version information and exit.

-h, --help

Display usage information and exit.

 

SORT CRITERIA

The following are valid sort criteria used to sort the individual slab caches and thereby determine what are the "top" slab caches to display. The default sort criteria is to sort by the number of objects ("o").

The sort criteria can also be changed while slabtop is running by pressing the associated character.

character	description	header
a	number of active objects	ACTIVE
b	objects per slab	OBJ/SLAB
c	cache size	CACHE SIZE
l	number of slabs	SLABS
v	number of active slabs	N/A
n	name	NAME:
o	number of objects	OBJS
p	pages per slab	N/A
s	object size	OBJ SIZE
u	cache utilization	USE

 

COMMANDS

slabtop accepts keyboard commands from the user during use. The following are supported. In the case of letters, both cases are accepted.

Each of the valid sort characters are also accepted, to change the sort routine. See the section SORT CRITERIA.

<SPACEBAR>

Refresh the screen.

Q

Quit the program.

 

FILES

/proc/slabinfo

slab information

 

SEE ALSO

free(1), ps(1), top(1), vmstat(8)  

NOTES

Currently, slabtop requires a 2.4 or later kernel (specifically, a version 1.1 or later /proc/slabinfo). Kernel 2.2 should be supported in the future.

The slabtop statistic header is tracking how many bytes of slabs are being used and is not a measure of physical memory. The 'Slab' field in the /proc/meminfo file is tracking information about used slab physical memory.

The CACHE SIZE column is not accurate, it's the upper limit of memory used by specific slab. When system using slub (most common case) is under high memory pressure, there are slab order fallbacks, which means "pages per slab" is not constant and may decrease.  

AUTHORS

Written by Chris Rivera and Robert Love.

slabtop was inspired by Martin Bligh's perl script, vmtop.  

REPORTING BUGS

Please send bug reports to

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Index

NAME

SYNOPSIS

DESCRIPTION

OPTIONS

SORT CRITERIA

COMMANDS

FILES

SEE ALSO

NOTES

AUTHORS

REPORTING BUGS