fs_usage.tproj/fs_usage.1

   1 .\" Copyright (c) 2000, Apple Computer, Inc.  All rights reserved.
   2 .\"
   3 .Dd November 7, 2002
   4 .Dt FS_USAGE 1
   5 .Os "Mac OS X"
   6 .Sh NAME
   7 .Nm fs_usage
   8 .Nd report system calls and page faults related to filesystem activity in
   9 real-time
  10 .Sh SYNOPSIS
  11 .Nm fs_usage [-e] [-w] [-f mode [-f mode] ...] [ pid|cmd [pid|cmd] ...]
  12 .Sh DESCRIPTION
  13 The
  14 .Nm fs_usage
  15 utility presents an ongoing display of system call usage information
  16 pertaining to filesystem activity.
  17 It requires root privileges due to the kernel tracing facility it uses to
  18 operate.
  19 By default the activity monitored includes all system processes except the
  20 running
  21 .Nm fs_usage
  22 process, Terminal, telnetd, sshd, rlogind, tcsh, csh and sh.
  23 These defaults can be overridden such that output is limited to include or
  24 exclude a list of processes specified by the user.
  25 .Pp
  26 The output presented by
  27 .Nm fs_usage
  28 is formatted according to the size of your window.
  29 A narrow window will display fewer columns of data.
  30 Use a wide window for maximum data display.
  31 You may override the window formatting restrictions
  32 by forcing a wide display with the
  33 .Fl w
  34 option.
  35 In this case, the data displayed will wrap
  36 when the window is not wide enough.
  37 .Pp
  38 The options are as follows:
  39 .Bl -tag -width Ds
  40 .\" ==========
  41 .It Fl e
  42 Specifying the
  43 .Fl e
  44 option generates output that excludes sampling
  45 of the running fs_usage tool.
  46 If a list of process ids or commands is also given,
  47 then those processes are also excluded from the sampled output.
  48 .\" ==========
  49 .It Fl f
  50 Specifying the
  51 .Fl f
  52 option turns on output filtering based on the
  53 .Pa mode
  54 provided.
  55 Multiple filtering options can be specified.
  56 By default no output filtering occurs.
  57 The supported modes are:
  58 .Pp
  59 .Pa  network
  60 Only network related output is displayed.
  61 .Pp
  62 .Pa filesys
  63 Only file system related output is displayed.
  64 .Pp
  65 .Pa cachehit
  66 In addition, display CACHE_HIT output.
  67 .\" ==========
  68 .It Fl w
  69 Specifying the
  70 .Fl w
  71 option forces a wider, more detailed output,
  72 regardless of the window size.
  73 .\" ==========
  74 .It  pid | cmd
  75 The sampled data can be limited to a list of process ids or commands.
  76 When a command name is given, all processes with that name will be sampled.
  77 Using the
  78 .Fl e
  79 option has the opposite effect,
  80 excluding sampled data relating to the given list
  81 of process ids or commands.
  82 .El
  83 .Pp
  84 If you set the DYLD_IMAGE_SUFFIX environment variable to
  85 .Dq Li _debug ,
  86 then an application will use the debug version of all libraries,
  87 including the Carbon FileManager.
  88 See
  89 .Xr dyld 1 .
  90 When
  91 .Nm fs_usage
  92 is run against a Carbon Application launched in this environment,
  93 then the high-level Carbon FileManager calls
  94 will be displayed bracketing the system calls that they are built on.
  95 .Pp
  96 The data columns displayed are as follows:
  97 .Bl -tag -width Ds
  98 .Pp
  99 .It TIMESTAMP
 100 TOD when call occurred.
 101 Wide mode will have millisecond granularity.
 102 .It CALL
 103 The name of the network or filesystem related call, page-in, page-out,
 104 or physical disk access.
 105 .It FILE DESCRIPTOR
 106 Of the form F=x, x is a file descriptor.
 107 Depending on the type of system call,
 108 this will be either an input value or a return value.
 109 .It BYTE COUNT
 110 Of the form B=x, x is the number of bytes requested by the call.
 111 .It [ERRNO]
 112 On error, the errno is displayed in brackets.
 113 .It PATHNAME
 114 Pathname of the file accessed (up to the last 28 bytes).
 115 .It FAULT ADDRESS
 116 Of the form A=0xnnnnnnnn,
 117 where 0xnnnnnnnn is the address being faulted.
 118 .It DISK BLOCK NUMBER
 119 Of the form D=0xnnnnnnnn,
 120 where 0xnnnnnnnn is the block number
 121 of the physical disk block being read or written.
 122 .It OFFSET
 123 Of the form O=0xnnnnnnnn, where 0xnnnnnnnn is a file offset.
 124 .It SELECT RETURN
 125 Of the form S=x, x is the number of ready descriptors returned
 126 by the select() system call.
 127 If S=0, the time limit expired.
 128 .It TIME INTERVAL(W)
 129 The elapsed time spent in the system call.
 130 A
 131 .Sq Li W
 132 after the elapsed time indicates the process was scheduled out
 133 during this file activity.
 134 In this case, the elapsed time includes the wait time.
 135 .It PROCESS NAME
 136 The process that made the system call.
 137 .El
 138 .Pp
 139 .Sh SAMPLE USAGE
 140 .Pp
 141 fs_usage -w -f filesys Mail
 142 .Pp
 143 .Nm fs_usage
 144 will display file system related data
 145 for all instances of processes named Mail.
 146 Maximum data output will be displayed in the window.
 147 .Sh SEE ALSO
 148 .Xr dyld 1 ,
 149 .Xr latency 1 ,
 150 .Xr sc_usage 1 ,
 151 .Xr top 1