# slabtop

## 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 fine-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
    


## 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.
    


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