idoptimize(1M)

idoptimize -- optimize a kernel based on workload

Synopsis

   idoptimize -s [module]...
   idoptimize -l [module]...
   idoptimize -c [module]...
   idoptimize -g [-m] [module]...
   idoptimize -L [module]...
   idoptimize -C [clobber]
   idoptimize -u

Description

idoptimize uses the technology provided by fur(1) to gather experimental data, analyze this data and rearrange the kernel code such that it runs faster for a given system's workload.

idoptimize has seven different forms. The first five represent the steps that most people will want to take to optimize their kernel. The last two are utility calls that might be useful.

For each version of the command that takes a list of modules, the default is to use the list of modules that are loaded into the current running kernel. In general, it should be unnecessary to supply arguments to any of them.

Step 1: idoptimize -s: This optional step is to make some of the loadable modules on the system static. fur can do a better job of optimizing a kernel if all of the modules that are being used are static.
Step 2: idoptimize -l: This step tells the system to rebuild the kernel so that it will take logging data during the next reboot. Reboot the system after this step. A logging kernel is VERY SLOW.
Step 3: idoptimize -c: This step clears the logs in the running kernel. It is executed on a kernel that is set up for logging (Step 2). One should clear the logs before running an experimental load.
Step 4: idoptimize -g: This step gets the logs from the running kernel and analyzes them. It should be run after the experiment is done. One can run many experiments by clearing the log before each experiment, running the experiment and then adding the -m option to idoptimize -g (to merge the results) each time.
Step 5: idoptimize -L: This step tells the system that the next rebuild of the system should not create a logging kernel. Reboot the system after this step and when the system comes up, the kernel is optimized.

The -C option is used to clear out files left from using idoptimize to save on disk space. If the this option is invoked, useful information will be lost, but the kernel will be returned to its original state, except for the effects of idoptimize -s.

The -u option undoes the effects of idoptimize -s.

Diagnostics

If a non-existent module is named, idoptimize fails. Also, if -c or -g is used with a kernel that has not been built for logging, idoptimize fails.

References

fur(1), idbuild(1M).