NAME

       kerneltop - shows kernel function usage in an interactive style like 'top'

SYNOPSIS

       kerneltop [ options ]

VERSION

       This manpage documents version 0.8 of the program.

DESCRIPTION

       The  kerneltop  command  uses the /proc/profile and the kernel system map to print ascii data on standard
       output, updated once a second. The output is organized in three columns: the first is the address of  the
       function, the second is the name of the C function in the kernel, and the third number of clock ticks the
       function has taken. The output is filled with blanks to ease readability, and can either be sorted by the
       number of ticks per function (the default), or the address of the function.

OPTIONS

       Available command line options:

       -m mapfile
              Specify  a  mapfile,  which  by  default  is  /boot/System.map,  or /boot/System.map-`uname -r` if
              /boot/System.map doesn't exist. You should specify the  map  file  on  the  command-line  if  your
              current kernel isn't the last one you compiled, or `uname -r` does not refer to the correct suffix
              for the current System.map file. If the name of the map file ends with `.gz' it is decompressed on
              the fly.

       -p profile
              Specify  a  different  profiling  buffer,  which by default is /proc/profile.  This should only be
              necessary if the proc filesystem is mounted somewhere other than /proc.

       -l lines
              Lines. Number of lines to print on the display. Default is 20 and the maximum is 100.

       -s seconds
              Sleep time between each pass in seconds. Default is 1 second.

       -t ticks
              Lower threshold number of ticks to print. Default is 1 tick.

       -u     Unsorted output. Default is sorted (by ticks). Note that unsorted output  is  actually  sorted  by
              address.

       -V     Version. This makes kerneltop print its version number and exit.

EXAMPLES

       Display 46 lines of output (useful for 50 line terminals):
          kerneltop -l 46

       Show only proceses that use 5 ticks or more:
          kerneltop -t 5

       Show unsorted output by default:
          kerneltop -u

INTERACTIVE Commands

       There  are  a  number  of  interactive  commands  available in kerneltop. The effect of these commands is
       documented above under OPTIONS.

        <h> or <?>: Help

       This is simply a list of available commands for the interactive mode.

        <l>: Lines

       Set number of console lines to use for display

        <s>: Seconds

       Set number of seconds between sample periods

        <t>: Threshold

       Set lower threshold for number of ticks required to be printed

        <q>: Quit

       Leaves the program

        <u>: Unsorted/Sorted

       Toggles between unsorted and sorted display (sorted by ticks)

BUGS

       kerneltop works with a 2.6.x or newer kernel. Do not expect previous kernels to  work,  but  they  might.
       YMMV.

       This  program  only  works  with  ELF  kernels.  The  change for a.out kernels is trivial, and left as an
       exercise to the a.out user.

       To enable profiling, the kernel must be rebooted, because  no  profiling  module  is  available,  and  it
       wouldn't be easy to build. To enable profiling, you can specify "profile=1" on the kernel commandline.

       See  Documentation/basic_profiling.txt  ,  which  can  be  found in the Linux kernel source tree for your
       kernel for more information.

       Profiling is disabled when interrupts are inhibited. This means that many  profiling  ticks  happen  when
       interrupts are re-enabled. Watch out for misleading information.

       Randy Dunlap <rddunlap@osdl.org>

FILES

       /proc/profile              A binary snapshot of the profiling buffer.
       /boot/System.map           The symbol table for the kernel.
       /usr/src/linux/*           The program being profiled :-)

AUTHOR

       This  program  is  written  by  Randy  Dunlap <rddunlap@osdl.org>, and is largely based on readprofile by
       Alessandro Rubini <rubini@ipvvis.unipv.it>.

SEE ALSO

       readprofile(1), top(1)

                                                    May 2004                                        KERNELTOP(1)