sys-utils/readprofile.1

   1 .TH READPROFILE 1 "January 1995"
   2 .UC 4
   3 .SH NAME
   4 readprofile - a tool to read kernel profiling information
   5 .SH SYNOPSIS
   6 .B readprofile
   7 [
   8 .I options
   9 ]
  10
  11 .SH VERSION
  12 This manpage documents version 1.1 of the program.
  13
  14 .SH DESCRIPTION
  15
  16 .LP
  17 The
  18 .B readprofile
  19 command uses the
  20 .B /proc/profile
  21 information to print ascii data on standard output.
  22 The output is
  23 organized in three columns: the first is the number of clock ticks,
  24 the second is the name of the C function in the kernel where those many
  25 ticks occurred, and the third is the normalized `load' of the procedure,
  26 calculated as a ratio between the number of thicks and the lenght of
  27 the procedure. The output is filled with blanks to ease readability.
  28
  29 .LP
  30 Available command line options are the following:
  31
  32 .TP
  33 .RB -m " mapfile"
  34 Specify a mapfile, which by default is
  35 .B /usr/src/linux/System.map.
  36 To ease use of
  37 .B readprofile
  38 with kernels in the 1.1.7x series, if the default file can't be opened,
  39 the alternate file
  40 .B /usr/src/linux/zSystem.map
  41 is tried.
  42 You should specify the map file on cmdline if your current kernel isn't the
  43 last one you compiled. If the name of the map file ends with `.gz' it
  44 is decompressed on the fly.
  45
  46 .TP
  47 .RB -p " pro-file"
  48 Specify a different profiling buffer, which by default is
  49 .B /proc/profile.
  50 Using a different pro-file is useful if you want to `freeze' the
  51 kernel profiling at some time and read it later. The
  52 .B /proc/profile
  53 file can be copied using `cat' or `cp'. If the name of the pro-file
  54 ends by `.gz' it is decompressed on the fly. The pro-file is such that
  55 .B gzip
  56 shrinks it by 50-100 times.
  57
  58 .TP
  59 .B -i
  60 Info. This makes
  61 .B readprofile
  62 only print the profiling step used by the kernel.
  63 The profiling step is the resolution of the profiling buffer, and
  64 is chosen during kernel configuration (through `make config').
  65 If the
  66 .B -t
  67 (terse) switch is used together with
  68 .B -i
  69 only the decimal number is printed.
  70
  71 .TP
  72 .B -a
  73 Print all symbols in the mapfile. By default the procedures with 0 reported
  74 ticks are not printed.
  75
  76 .TP
  77 .B -r
  78 Reset the profiling buffer. This can only be invoked by root, because
  79 .B /proc/profile
  80 is readable by everybody but writable only by the superuser.
  81
  82 .TP
  83 .B -t
  84 Terse. This causes the output to be unfilled. It is the format used in the
  85 first release of
  86 .B readprofile.
  87
  88 .TP
  89 .B -v
  90 Verbose. The output is organized in four columns and filled with blanks.
  91 The first column is the RAM address of a kernel function, the second is
  92 the name of the function, the third is the number of clock ticks and the
  93 last is the normalized load.
  94
  95 .TP
  96 .B -V
  97 Version. This makes
  98 .B readprofile
  99 print its version number and exit.
 100
 101 .SH EXAMPLES
 102 Browse the profiling buffer ordering by clock ticks:
 103 .nf
 104    readprofile | sort -nr | less
 105
 106 .fi
 107 Print the 20 most loaded procedures:
 108 .nf
 109    readprofile | sort -nr +2 | head -20
 110
 111 .fi
 112 Print only filesystem profile:
 113 .nf
 114    readprofile | grep _ext2
 115
 116 .fi
 117 Look at all the kernel information, with ram addresses"
 118 .nf
 119    readprofile -av | less
 120
 121 .fi
 122 Browse a gzipped `freezed' profile buffer for a non current kernel:
 123 .nf
 124    readprofile -p ~/profile.freeze.gz -m /zImage.map
 125
 126 .fi
 127
 128 .SH BUGS
 129
 130 .LP
 131 .B readprofile
 132 needs a kernel version 1.1.73 or newer, because
 133 .B /proc/profile
 134 is absent
 135 in older versions.
 136
 137 .LP
 138 To enable profiling, the kernel must be reconfigured, recompiled, and
 139 rebooted. No profiling module is available, and it wouldn't be easy to
 140 build. So this can be construed as a feature.
 141
 142 .LP
 143 Profiling is disabled when interrupts are inhibited. This means that many
 144 profiling ticks happen when interrupts are re-enabled. Watch out for
 145 misleading information.
 146
 147 .SH AUTHOR
 148
 149 Readprofile and /proc/profile are by Alessandro Rubini (rubini@ipvvis.unipv.it)
 150
 151 .SH FILES
 152 .nf
 153 /proc/profile              A binary snapshot of the profiling buffer.
 154 /usr/src/linux/System.map  The symbol table for the kernel.
 155 /usr/src/linux/zSystem.map Old name for the symbol table.
 156
 157 /usr/src/linux/*           The program being profiled :-)
 158 .fi
 159