5.1 Using Script Hooks to Add New Functionality
Auto-pilot's benchmarking scripts include nine points in which you can
insert your own code without modifying the original scripts. These
hooks allow you to benchmark new file systems, compile new programs, and
measure new quantities. The first three hooks are generic, and not related to
- The first argument to a measurement hook describes at what point the
hook is being executed. premeasure indicates that it is before
the measurement is actually taking place. start indicates that
measurement should begin, and end indicates that measurement
should complete. For example, during start a measurement hook
could save important system state (e.g., the number of I/O operations to
date), and during end the same quantity could be measured and the
original value subtracted from the current value. During end,
the hook must print a line of the format name =
value, which is added to the measurement block. During
final new blocks can be added.
The remaining arguments are the command that is being measured.
compilecommand PACKAGE PKGFILE
- The compilecommand hook allows a series of compilation commands to be
defined for new packages. The first argument is the name of the package
to be compiled, and the second argument is the package file that is
If the hook returns success, then it must set the environment variable
CMDLIST to an array containing each command to execute. For
example, to compile GCC the following statements are used:
- To execute remote commands on another machine, some Auto-pilot scripts
execute apremote.sh. To add new commands to apremote.sh,
you can define an
apremote hook. The first argument is the
command passed to apremote.sh, and the remaining arguments are
the arguments for that command.
The remaining hooks are used by the file system setup scripts.
mkfsopts FS TESTDEV BLOCKSIZE FSSIZE
mkfsopts hook is called before mkfs. This hook
takes four arguments, the file system time, the device, the block size,
and the file system size. It should print any additional options to pass to
mkfs on stdout.
mkfs FS TESTDEV BLOCKSIZE FSSIZE
- For Ext2, Ext3, and Reiserfs, fs-setup.sh executes the
appropriate mkfs command, but for other types of file systems
it relies on the
mkfs hook to properly format the file system.
The mkfs hook takes the same arguments as mkfsopts,
and formats the file system according to the arguments and environment
tunefs FS TESTDEV
- After the file system is formatted, a tunefs hook is called
with two arguments: the file system type and the device. The tunefs
hook can modify file system properties. For example, a tunefs hook can
toggle directory indexing on an Ext2 or Ext3 partition.
mount FSTYPE TESTDEV TESTROOT
- Before a file system is mounted, a mount hook is called with arguments
$FSTYPE $TESTDEV $TESTROOT. This hook can perform pre-mount
operations, or mount the file system itself. To suppress
fs-setup.sh from mounting the file system, the hook can set
DOMOUNT to zero.
postmount FSTYPE TESTDEV TESTROOT
- After a file system is mounted, a postmount hook is called with the same
arguments as the mount hook.
unmount TESTDEV TESTROOT
- The unmount hook should unmount the file system mounted on
TESTROOT and the file system located on TESTDEV.