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 by forcing a wide display
  32 with the
  33 .Fl w
  34 option.
  35 In this case, the data displayed will wrap when the window is not wide enough.
  36 .Pp
  37 The options are as follows:
  38 .Bl -tag -width Ds
  39 .It Fl e
  40 Specifying the
  41 .Fl e
  42 option generates output that excludes sampling
  43 of the running fs_usage tool.
  44 If a list of process ids or commands is also given, then those processes are
  45 also excluded from the sampled output.
  46 .It Fl w
  47 Specifying the
  48 .Fl w
  49 option forces a wider, more detailed output, regardless of the window size.
  50 .It Fl f
  51 Specifying the
  52 .Fl f
  53 option turns on output filtering based on the
  54 .Pa mode
  55 provided.
  56 Multiple filtering options can be specified.
  57 By default no output filtering occurs.
  58 The supported modes are:
  59 .Pp
  60 .Pa  network
  61 Only network related output is displayed.
  62 .Pp
  63 .Pa filesys
  64 Only file system related output is displayed.
  65 .Pp
  66 .Pa cachehit
  67 In addition, display CACHE_HIT output.
  68 .It  pid | cmd
  69 The sampled data can be limited to a list of process ids or commands.
  70 When a command name is given, all processes with that name will be sampled.
  71 Using the
  72 .Fl e
  73 option has the opposite effect, excluding sampled data relating to the given
  74 list of process ids or commands.
  75 .El
  76 .Pp
  77 If you set the DYLD_IMAGE_SUFFIX environment variable to
  78 .Dq Li _debug ,
  79 then an application will use the debug version of all libraries including the
  80 Carbon FileManager.
  81 See
  82 .Xr dyld 1 .
  83 When
  84 .Nm fs_usage
  85 is run against a Carbon Application launched in this environment, then the
  86 high level Carbon FileManager calls will be displayed bracketing the system
  87 calls that they are built on.
  88 .Pp
  89 The data columns displayed are as follows:
  90 .Bl -tag -width Ds
  91 .Pp
  92 .It TIMESTAMP
  93 TOD when call occurred.
  94 Wide mode will have millisecond granularity.
  95 .It CALL
  96 The name of the network or filesystem related call, page-in, page-out or physical disk access.
  97 .It FILE DESCRIPTOR
  98 Of the form F=x, x is a file descriptor.
  99 Depending on the type of system call, this will be either an input value or a
 100 return value.
 101 .It BYTE COUNT
 102 Of the form B=x, x is the number of bytes requested by the call.
 103 .It [ERRNO]
 104 On error, the errno is displayed in brackets.
 105 .It PATHNAME
 106 Pathname of the file accessed (up to the last 28 bytes).
 107 .It FAULT ADDRESS
 108 Of the form A=0xnnnnnnnn, where 0xnnnnnnnn is the address being faulted.
 109 .It DISK BLOCK NUMBER
 110 Of the form D=0xnnnnnnnn, where 0xnnnnnnnn is the block number of the physical
 111 disk block being read or written.
 112 .It OFFSET
 113 Of the form O=0xnnnnnnnn, where 0xnnnnnnnn is a file offset.
 114 .It SELECT RETURN
 115 Of the form S=x, x is the number of ready descriptors returned by the select()
 116 system call.
 117 If S=0, the time limit expired.
 118 .It TIME INTERVAL(W)
 119 The elapsed time spent in the system call.
 120 A
 121 .Sq Li W
 122 after the elapsed time indicates the process was scheduled out during this file
 123 activity.
 124 In this case, the elapsed time includes the wait time.
 125 .It PROCESS NAME
 126 The process that made the system call.
 127 .El
 128 .Pp
 129 .Sh SAMPLE USAGE
 130 .Pp
 131 fs_usage -w -f filesys Mail
 132 .Pp
 133 .Nm fs_usage
 134 will display file system related data for all instances of processes named Mail.
 135 Maximum data output will be displayed in the window.
 136 .Sh SEE ALSO
 137 .Xr top 1 ,
 138 .Xr sc_usage 1 ,
 139 .Xr latency 1 ,
 140 .Xr dyld 1