Operation
---------

When bootchartd is started by the kernel (passed init=/sbin/bootchartd), it
will first start boot logging in background and then exec /sbin/init or an
alternative init process.
The boot logger will mount a tmpfs file system for log file storage and wait
for /proc to be mounted.  It will then run several logging functions in
parallel and wait for the boot process to end (i.e. one of the predefined
processes for runlevels 2, 3 or 5 is running).


Monitoring applications
-----------------------

In addition to the boot process, the bootchartd logger may also be used to
profile a running system or specific applications.  This may performed by
regular users as well, by using the following procedure:

  1. Copy the default bootchartd configuration file locally:

     $ cp /etc/bootchartd.conf /home/joe/tmp/

  2. Edit /home/joe/tmp/bootchartd.conf and replace the BOOTLOG_DEST
     value with a directory with write permissions, e.g.
       
       BOOTLOG_DEST=/home/joe/tmp/bootchart.tgz

  3. Run bootchartd from within /home/joe/tmp/, profiling the system
     in general or a specific application:

     $ cd /home/joe/tmp/
     
     # to profile the system in general:
     $ /sbin/bootchart start; sleep 5; /sbin/bootchartd stop
     
     # to profile a specific application, e.g. evolution:
     $ /sbin/bootchart start evolution

  4. Render the generated log file:

     $ /usr/bin/bootchart /home/joe/tmp/bootchart.tgz

     Alternatively, upload the log tarball to the renderer web service.


Log files
---------

The bootchartd script will create various log files.  Note that all statistics
log entries start with the time, specified as uptime in jiffies (1/100 s).
Log entries are written every 0.2 seconds by default.  Detailed information
about the /proc entries is available in the proc(5) manual page.

The files available in /var/log/bootchart.tgz are:

1. header

   Basic information about the system and logger.  The following properties
   are set (with sample values):

   === header ===
   version = 0.9
   title = Boot chart for serenity.klika.si (Wed Jan 19 22:21:53 CET 2005)
   system.uname = Linux 2.6.10-1.741_FC3 #1 Thu Jan 13 16:38:22 EST 2005 i686 GNU/Linux
   system.release: Fedora Core release 3 (Heidelberg)
   system.cpu = model name : Intel(R) Pentium(R) M processor 1500MHz (1)
   system.kernel.options = ro root=/dev/vg0/root vga=0x318 quiet grub
   ==============


2. proc_stat.log

   The CPU statistics collected from /proc/stat.
   
   Example:
   
   === proc_stat.log ===
   691
   cpu  8 0 141 313 230 0 0
   cpu0 8 0 141 313 230 0 0
   intr 7454 6943 8 0 1 3 1 0 0 0 1 1 1 99 0 373 23
   ctxt 4607
   btime 1106875682
   processes 531
   procs_running 2
   procs_blocked 1

   ...
   =====================


3. proc_diskstats.log (optional)

   The disk IO statistics collected from /proc/diskstats.  Note that these
   are only available when using a 2.6 kernel (or a patched 2.4 kernel).
   
   Example:
   
   === proc_diskstats.log ===
   704
      1    0 ram0 0 0 0 0 0 0 0 0 0 0 0
      1    1 ram1 0 0 0 0 0 0 0 0 0 0 0
      ...
      3    0 hda 357 18 7963 7619 0 0 0 0 3 2522 7789
      ...

   ...
   ==========================


4. proc_ps.log

   Process status information, collected from /proc/[PID]/stat files.
   Used to reconstruct the process tree and track process states and CPU
   usage.  Example:
   
   === proc_ps.log ===
   692
   1 (init) S 0 0 0 0 -1 8388864 656 ...
   138 (kblockd/0) S 3 0 0 0 -1 32832 0 ...
   146 (khubd) S 1 1 1 0 -1 64 0 ...
   16 (kacpid) S 3 0 0 0 -1 32832 0 ...
   2 (ksoftirqd/0) S 1 0 0 0 -1 32832 ...

   ...
   ==============

 
5. init_pidname.log (optional)
   
   The PID to process name mapping file.  Used for Gentoo, where many init
   scripts are sourced and thus shown as "rc boot" or "rc default" in the
   process listing.  The Gentoo init patch however will maintain this log
   file by storing the actual script names and mapping them to PIDs.
   Example:
   
   === init_pidname.log ===
   2969=checkroot
   2996=hostname
   3003=modules
   7263=coldplug
   ...
   ===================


6. kernel_pacct (optional)

   Process accounting information.  Created if BSD process accounting v3 is
   configured when compiling the kernel (CONFIG_BSD_PROCESS_ACCT_V3).  The
   GNU accounting tools also need to be installed (psacct or acct package).
   
   The file contains detailed process information, useful for filling in any
   process dependency blanks caused by the polling nature of
   /proc/[PID]/stat logging.  The file is binary and is defined in
   include/linux/acct.h.
   
   General information about process accounting is available in the HOWTO:
   http://www.tldp.org/HOWTO/Process-Accounting/


Alternative init processes
--------------------------

Alternative init processes (e.g. initng) may be specified using the
bootchart_init kernel command line option, e.g.:

  init=/sbin/bootchartd bootchart_init=/sbin/initng

In this case, bootchartd will execute /sbin/initng instead of the default
/sbin/init.



http://www.bootchart.org
Ziga Mahkovec  <ziga.mahkovec@klika.si>