Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

choice

        prompt "Preemption Model"

        default PREEMPT_NONE

config PREEMPT_NONE

        bool "No Forced Preemption (Server)"

        help

          This is the traditional Linux preemption model, geared towards

          throughput. It will still provide good latencies most of the

          time, but there are no guarantees and occasional longer delays

          are possible.

          Select this option if you are building a kernel for a server or

          scientific/computation system, or if you want to maximize the

          raw processing power of the kernel, irrespective of scheduling

          latencies.

config PREEMPT_VOLUNTARY

        bool "Voluntary Kernel Preemption (Desktop)"

        help

          This option reduces the latency of the kernel by adding more

          "explicit preemption points" to the kernel code. These new

          preemption points have been selected to reduce the maximum

          latency of rescheduling, providing faster application reactions,

          at the cost of slightly lower throughput.

          This allows reaction to interactive events by allowing a

          low priority process to voluntarily preempt itself even if it

          is in kernel mode executing a system call. This allows

          applications to run more 'smoothly' even when the system is

          under load.

          Select this if you are building a kernel for a desktop system.

config PREEMPT

        bool "Preemptible Kernel (Low-Latency Desktop)"

        help

          This option reduces the latency of the kernel by making

          all kernel code (that is not executing in a critical section)

          preemptible.  This allows reaction to interactive events by

          permitting a low priority process to be preempted involuntarily

          even if it is in kernel mode executing a system call and would

          otherwise not be about to reach a natural preemption point.

          This allows applications to run more 'smoothly' even when the

          system is under load, at the cost of slightly lower throughput

          and a slight runtime overhead to kernel code.

          Select this if you are building a kernel for a desktop or

          embedded system with latency requirements in the milliseconds

          range.

endchoice

config PREEMPT_BKL

        bool "Preempt The Big Kernel Lock"

        depends on SMP || PREEMPT

        default y

        help

          This option reduces the latency of the kernel by making the

          big kernel lock preemptible.

          Say Y here if you are building a kernel for a desktop system.

          Say N if you are unsure.