doc/rst/dyld_usage.rst

   1 dyld_usage - report dynamic linker activity in real-time
   2 ========================================================
   3
   4 SYNOPSIS
   5 --------
   6
   7 :program:`dyld_usage` **[-e] [-f mode] [-j] [-h] [-t seconds] [-R rawfile [-S start_time]
   8 [-E end_time]] [pid | cmd [pid | cmd] ...]**
   9
  10 DESCRIPTION
  11 -----------
  12 The :program:`dyld_usage` utility presents an ongoing display of information
  13 pertaining to dynamic linker activity within one or more processes. It requires
  14 root privileges due to the kernel tracing facility it uses to operate. By
  15 default :program:`dyld_usage` monitors `dyld` activity in all processes except
  16 the running `dyld_usage` process, `Terminal`, `telnetd`, `sshd`, `rlogind`,
  17 `tcsh`, `csh`, and `sh`. These defaults can be overridden such that output is
  18 limited to include or exclude a list of processes specified on the command line.
  19 Processes may be specified either by file name or by process id.
  20
  21 The output of :program:`dyld_usage` is formatted according to the size of your
  22 window. A narrow window will display fewer columns of data. Use a wide window
  23 for maximum data display.
  24
  25 OPTIONS
  26 -------
  27 :program:`dyld_usage` supports the following options:
  28
  29 .. option:: -e
  30
  31   Exclude the specified list of pids and commands from the sample, and exclude
  32   :program:`dyld_usage` by default.
  33
  34   .. option:: -j
  35
  36   Display output in JSON format.
  37
  38 .. option:: -h
  39
  40   Display usage information and exit.
  41
  42 .. option:: -R
  43
  44   Specify a raw trace file to process.
  45
  46 .. option:: -t
  47
  48   Specify timeout in seconds (for use in automated tools).
  49
  50 DISPLAY
  51 -------
  52
  53 The data columns displayed are as follows:
  54
  55   TIMESTAMP
  56     Time of day when call occurred.
  57
  58   OPERATION
  59     The `dyld` operation triggered by the process. Typically these operations
  60     are triggered by process launch or via a ``dlopen`` or ``dlsym`` system
  61     call. System call entries include both the parameters to the system call and
  62     the system call's return code (e.g., 0 on success).
  63
  64   TIME INTERVAL
  65     The elapsed time spent in the dynamic linker operation or system call.
  66
  67   PROCESS NAME
  68     The process that generated the dynamic linker activity. If space allows, the
  69     thread id will be appended to the process name (i.e., Mail.nnn).
  70
  71
  72 SAMPLE USAGE
  73 ------------
  74
  75  ``sudo dyld_usage Mail``
  76
  77  :program:`dyld_usage` will display dynamic link operations for all instances of
  78  processes named Mail.
  79
  80 SEE ALSO
  81 --------
  82
  83 :manpage:`dyld(1)`, :manpage:`fs_usage(1)`
  84