SYNOPSIS

       readprofile [ options ]

VERSION

       This manpage documents version 2.0 of the program.

DESCRIPTION

       The  readprofile  command  uses  the /proc/profile information to print
       ascii data on standard output.  The output is organized in  three  col-
       umns: the first is the number of clock ticks, the second is the name of
       the C function in the kernel where those many ticks occurred,  and  the
       third  is the normalized `load' of the procedure, calculated as a ratio
       between the number of ticks and the length of the procedure. The output
       is filled with blanks to ease readability.


       Available command line options are the following:


       -m mapfile
              Specify  a  mapfile,  which  by  default  is /usr/src/linux/Sys-
              tem.map.  You should specify the map file  on  cmdline  if  your
              current  kernel  isn't the last one you compiled. If the name of
              the map file ends with `.gz' it is decompressed on the fly.


       -p pro-file
              Specify a  different  profiling  buffer,  which  by  default  is
              /proc/profile.  Using a different pro-file is useful if you want
              to `freeze' the kernel profiling at some time and read it later.
              The  /proc/profile file can be copied using `cat' or `cp'. There
              is no more support for compressed profile buffers, like in read-
              profile-1.1,  because  the program needs to know the size of the
              buffer in advance.


       -i     Info. This makes readprofile only print the profiling step  used
              by the kernel.  The profiling step is the resolution of the pro-
              filing  buffer,  and  is  chosen  during  kernel   configuration
              (through  `make  config'),  or in the kernel's command line.  If
              the -t (terse) switch is used together with -i only the  decimal
              number is printed.


       -a     Print all symbols in the mapfile. By default the procedures with
              0 reported ticks are not printed.


       -b     Print individual histogram-bin counts.

              requires superuser privileges.


       -v     Verbose. The output is organized in four columns and filled with
              blanks.  The first column is the RAM address of a  kernel  func-
              tion,  the  second is the name of the function, the third is the
              number of clock ticks and the last is the normalized load.


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

EXAMPLES

       Browse the profiling buffer ordering by clock ticks:
          readprofile | sort -nr | less

       Print the 20 most loaded procedures:
          readprofile | sort -nr +2 | head -20

       Print only filesystem profile:
          readprofile | grep _ext2

       Look at all the kernel information, with ram addresses"
          readprofile -av | less

       Browse a `freezed' profile buffer for a non current kernel:
          readprofile -p ~/profile.freeze -m /zImage.map.gz

       Request profiling at 2kHz per CPU, and reset the profiling buffer
          sudo readprofile -M 20

BUGS

       readprofile   only  works  with  an  1.3.x  or  newer  kernel,  because
       /proc/profile changed in the step from 1.2 to 1.3


       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  pro-
       filing,  you  can specify "profile=2" (or another number) on the kernel
       commandline.  The number you specify is the two-exponent used  as  pro-
       filing step.


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