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)