ia64/linux-2.6.18-xen.hg

annotate kernel/Kconfig.preempt @ 798:b02a90bf5bbc

ACPI: Backport missing part for T-State MSR support

Part of below kernel commit was missed while packporting T-State
support.

commit f79f06ab9f86d7203006d2ec8992ac80df36a34e
Author: Zhao Yakui <yakui.zhao@intel.com>
Date: Thu Nov 15 17:06:36 2007 +0800

ACPI: Enable MSR (FixedHW) support for T-States

Add throttling control via MSR when T-states uses
the FixHW Control Status registers.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Li Shaohua <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

Signed-off-by: Wei Gang <gang.wei@intel.com>
author Keir Fraser <keir.fraser@citrix.com>
date Mon Mar 02 10:53:59 2009 +0000 (2009-03-02)
parents a533be77c572
children
rev   line source
ian@0 1
ian@0 2 choice
ian@0 3 prompt "Preemption Model"
ian@0 4 default PREEMPT_NONE
ian@0 5
ian@0 6 config PREEMPT_NONE
ian@0 7 bool "No Forced Preemption (Server)"
ian@0 8 help
ian@0 9 This is the traditional Linux preemption model, geared towards
ian@0 10 throughput. It will still provide good latencies most of the
ian@0 11 time, but there are no guarantees and occasional longer delays
ian@0 12 are possible.
ian@0 13
ian@0 14 Select this option if you are building a kernel for a server or
ian@0 15 scientific/computation system, or if you want to maximize the
ian@0 16 raw processing power of the kernel, irrespective of scheduling
ian@0 17 latencies.
ian@0 18
ian@0 19 config PREEMPT_VOLUNTARY
ian@0 20 bool "Voluntary Kernel Preemption (Desktop)"
ian@0 21 help
ian@0 22 This option reduces the latency of the kernel by adding more
ian@0 23 "explicit preemption points" to the kernel code. These new
ian@0 24 preemption points have been selected to reduce the maximum
ian@0 25 latency of rescheduling, providing faster application reactions,
ian@0 26 at the cost of slighly lower throughput.
ian@0 27
ian@0 28 This allows reaction to interactive events by allowing a
ian@0 29 low priority process to voluntarily preempt itself even if it
ian@0 30 is in kernel mode executing a system call. This allows
ian@0 31 applications to run more 'smoothly' even when the system is
ian@0 32 under load.
ian@0 33
ian@0 34 Select this if you are building a kernel for a desktop system.
ian@0 35
ian@0 36 config PREEMPT
ian@0 37 bool "Preemptible Kernel (Low-Latency Desktop)"
ian@26 38 depends on !XEN
ian@0 39 help
ian@0 40 This option reduces the latency of the kernel by making
ian@0 41 all kernel code (that is not executing in a critical section)
ian@0 42 preemptible. This allows reaction to interactive events by
ian@0 43 permitting a low priority process to be preempted involuntarily
ian@0 44 even if it is in kernel mode executing a system call and would
ian@0 45 otherwise not be about to reach a natural preemption point.
ian@0 46 This allows applications to run more 'smoothly' even when the
ian@0 47 system is under load, at the cost of slighly lower throughput
ian@0 48 and a slight runtime overhead to kernel code.
ian@0 49
ian@0 50 Select this if you are building a kernel for a desktop or
ian@0 51 embedded system with latency requirements in the milliseconds
ian@0 52 range.
ian@0 53
ian@0 54 endchoice
ian@0 55
ian@0 56 config PREEMPT_BKL
ian@0 57 bool "Preempt The Big Kernel Lock"
ian@0 58 depends on SMP || PREEMPT
ian@0 59 default y
ian@0 60 help
ian@0 61 This option reduces the latency of the kernel by making the
ian@0 62 big kernel lock preemptible.
ian@0 63
ian@0 64 Say Y here if you are building a kernel for a desktop system.
ian@0 65 Say N if you are unsure.
ian@0 66