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bitesize.d(1)                   USER COMMANDS                  bitesize.d(1)




NAME

       bitesize.d - analyse disk I/O size by process. Uses DTrace.


SYNOPSIS

       bitesize.d


DESCRIPTION

       This produces a report for the size of disk events caused by processes.
       These are the disk events sent by the block I/O driver.

       If applications must use the disks, we  generally  prefer  they  do  so
       sequentially with large I/O sizes, or larger "bites".

       Since  this  uses  DTrace, only users with root privileges can run this
       command.


EXAMPLES

       Sample until Ctrl-C is hit then print report,
              # bitesize.d



FIELDS

       PID    process ID

       CMD    command and argument list

       value  size in bytes

       count  number of I/O operations



NOTES

       The application may be requesting smaller sized operations,  which  are
       being rounded up to the nearest sector size or UFS block size.

       To  analyse  what the application is requesting, DTraceToolkit programs
       such as Proc/fddist may help.



DOCUMENTATION

       See the DTraceToolkit for further documentation under the  Docs  direc-
       tory. The DTraceToolkit docs may include full worked examples with ver-
       bose descriptions explaining the output.


EXIT

       bitesize.d will sample until Ctrl-C is hit.


AUTHOR

       Brendan Gregg [Sydney, Australia]


SEE ALSO

       iosnoop(1M), seeksize(1M), dtrace(1M)




version 1.00                     Jun 15, 2005                   bitesize.d(1)

Mac OS X 10.6 - Generated Thu Sep 17 20:07:13 CDT 2009
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