To facilitate the comparative evaluation of alternative CPU schedulers a patch that allows the run time selection of CPU scheduler between version 7.7 of Con Kolivas's staircase scheduler ("sc") and the priority based scheduler with interactive and throughput bonuses ("pb") has been created. This patch is available for download at:
<http://prdownloads.sourceforge.net/cpuse/patch-2.6.7-spa_hydra_FULL-v1.2?download>
The file /proc/sys/kernel/cpusched/mode has been added to those provided by the "pb" to control which of the schedulers is in control. The string "sc" is used to select the staircase scheduler and "pb" to select the priority based scheduler described above. The staircase scheduler control parameters "compute" and "interactive" have been moved into /proc/sys/kernel/cpusched along with the "pb" scheduler control parameters. The scheduler starts in the "sc" mode. A primitive Glade/PyGTK GUI that provides the ability to switch between schedulers and to control scheduler parameters is available at:
<http://prdownloads.sourceforge.net/cpuse/gcpuctl_hydra-1.0.tar.gz?download>
This GUI should also work with a standard version of Con Kolivas's staircase scheduler as well as the version based on my single priority array patch:
<http://prdownloads.sourceforge.net/cpuse/patch-2.6.7-spa_sc_FULL-v1.2?download>
and the basic priority based scheduler:
<http://prdownloads.sourceforge.net/cpuse/patch-2.6.7-spa_pb_FULL-v1.2?download>
and, for those so inclined, these patches broken into smaller parts for easier digestion are available at:
<https://sourceforge.net/projects/cpuse/>
An entitlement based "eb" scheduler will be added to the selection available in the near future.
Controls:
base_promotion_interval -- (milliseconds) controls the interval between successive promotions (is multiplied by the number of active tasks on the CPU in question) NB no promotion occurs if there are less than 2 active tasks
time_slice -- (milliseconds) the size of the time slice (i.e. how long it will be allowed to hold the CPU before it is kicked off to allow other tasks a chance to run) that is allocated to a task when it becomes active or finishes a time slice. (min is 1 millisec and max is 1 second).
max_ia_bonus -- (a value between 0 and 10) that determines the maximum interactive bonus that a task can acquire
initial_ia_bonus -- (a value between 0 and 10) that determines the initial interactive bonus that a newly forked task will be given. This value will be capped by the max_ia_bonus.
ia_threshold -- (parts per thousand) is the sleep to (sleep + on_cpu) ratio above which a task will have its interactive bonus increased asymptotically towards the maximum
cpu_hog_threshold -- (parts per thousand) is the usage rate above which a task will be considered a CPU hog and start to lose interactive bonus points if it has any
max_tpt_bonus -- (a value between 0 and 9) that determines the maximum throughput bonus that tasks may be awarded
log_at_exit - (0 or 1) turns off/on the logging of tasks' scheduling statistics at exit. This feature is useful for determining the scheduling characteristics of relatively short lived tasks that run as part of some larger job such as a kernel build where trying to get time series data is impractical.
compute -- (0 or 1) turn on/off the staircase schedulers "compute" switch
interactive -- (0 or 1) turn on/off the staircase schedulers "interactive" mode