linux/kernel
Ingo Molnar f8cbd99bd3 [PATCH] sched: voluntary kernel preemption
This patch adds a new preemption model: 'Voluntary Kernel Preemption'.  The
3 models can be selected from a new menu:

            (X) No Forced Preemption (Server)
            ( ) Voluntary Kernel Preemption (Desktop)
            ( ) Preemptible Kernel (Low-Latency Desktop)

we still default to the stock (Server) preemption model.

Voluntary preemption works by adding a cond_resched()
(reschedule-if-needed) call to every might_sleep() check.  It is lighter
than CONFIG_PREEMPT - at the cost of not having as tight latencies.  It
represents a different latency/complexity/overhead tradeoff.

It has no runtime impact at all if disabled.  Here are size stats that show
how the various preemption models impact the kernel's size:

    text    data     bss     dec     hex filename
 3618774  547184  179896 4345854  424ffe vmlinux.stock
 3626406  547184  179896 4353486  426dce vmlinux.voluntary   +0.2%
 3748414  548640  179896 4476950  445016 vmlinux.preempt     +3.5%

voluntary-preempt is +0.2% of .text, preempt is +3.5%.

This feature has been tested for many months by lots of people (and it's
also included in the RHEL4 distribution and earlier variants were in Fedora
as well), and it's intended for users and distributions who dont want to
use full-blown CONFIG_PREEMPT for one reason or another.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25 16:24:45 -07:00
..
irq [PATCH] make various thing static 2005-06-24 00:06:43 -07:00
power [PATCH] swsusp: only allow it when it makes sense 2005-06-25 16:24:34 -07:00
acct.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
audit.c AUDIT: Unify auid reporting, put arch before syscall number 2005-05-23 21:35:28 +01:00
auditsc.c AUDIT: Record working directory when syscall arguments are pathnames 2005-05-27 12:17:28 +01:00
capability.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
compat.c [PATCH] Fix get_compat_sigevent() 2005-04-16 15:24:01 -07:00
configs.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cpu.c [PATCH] i386 CPU hotplug 2005-06-25 16:24:29 -07:00
cpuset.c [PATCH] Dynamic sched domains: cpuset changes 2005-06-25 16:24:45 -07:00
dma.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
exec_domain.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
exit.c [PATCH] Optimize sys_times for a single thread process 2005-06-23 09:45:30 -07:00
extable.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
fork.c [PATCH] sched: consolidate sbe sbf 2005-06-25 16:24:44 -07:00
futex.c [PATCH] convert that currently tests _NSIG directly to use valid_signal() 2005-05-01 08:59:14 -07:00
intermodule.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
itimer.c [PATCH] setitimer timer expires too early 2005-05-05 16:36:41 -07:00
kallsyms.c [PATCH] ppc32: platform-specific functions missing from kallsyms. 2005-05-05 16:36:31 -07:00
Kconfig.hz [PATCH] i386: Selectable Frequency of the Timer Interrupt 2005-06-23 09:45:10 -07:00
Kconfig.preempt [PATCH] sched: voluntary kernel preemption 2005-06-25 16:24:45 -07:00
kfifo.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
kmod.c [PATCH] Keys: Pass session keyring to call_usermodehelper() 2005-06-24 00:05:18 -07:00
kprobes.c [PATCH] jprobes: allow a jprobe to coexist with muliple kprobes 2005-06-23 09:45:25 -07:00
ksysfs.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
kthread.c [PATCH] use smp_mb/wmb/rmb where possible 2005-05-01 08:58:47 -07:00
Makefile [PATCH] ppc64: remove hidden -fno-omit-frame-pointer for schedule.c 2005-05-05 16:36:32 -07:00
module.c [PATCH] make various thing static 2005-06-24 00:06:43 -07:00
panic.c [SPARC]: Stop-A printk cleanup 2005-04-24 20:38:02 -07:00
params.c [PATCH] sysfs: (rest) if show/store is missing return -EIO 2005-06-20 15:15:03 -07:00
pid.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
posix-cpu-timers.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
posix-timers.c [PATCH] posix-timers: use try_to_del_timer_sync() 2005-06-23 09:45:17 -07:00
printk.c [PATCH] CPU hotplug printk fix 2005-06-25 16:24:34 -07:00
profile.c [PATCH] profile.c: `schedule' parsing fix 2005-05-17 07:59:21 -07:00
ptrace.c [PATCH] convert that currently tests _NSIG directly to use valid_signal() 2005-05-01 08:59:14 -07:00
rcupdate.c [PATCH] Deprecate synchronize_kernel, GPL replacement 2005-05-01 08:59:04 -07:00
resource.c [PATCH] pci enumeration on ixp2000: overflow in kernel/resource.c 2005-04-16 15:25:58 -07:00
sched.c [PATCH] Dynamic sched domains: sched changes 2005-06-25 16:24:45 -07:00
seccomp.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
signal.c [PATCH] Software suspend and recalc sigpending bug fix 2005-06-23 09:45:27 -07:00
softirq.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
spinlock.c [PATCH] spin_unlock_bh() and preempt_check_resched() 2005-05-21 10:46:48 -07:00
stop_machine.c [PATCH] smp_processor_id() cleanup 2005-06-21 18:46:13 -07:00
sys_ni.c [PATCH] VM: early zone reclaim 2005-06-21 18:46:14 -07:00
sys.c [PATCH] properly stop devices before poweroff 2005-06-25 16:24:33 -07:00
sysctl.c [PATCH] setuid core dump 2005-06-23 09:45:26 -07:00
time.c [PATCH] time interpolator: Fix settimeofday inaccuracy 2005-04-28 08:13:58 -07:00
timer.c [PATCH] preempt_count is int - remove cast and don't assign to unsigned type 2005-06-23 09:45:19 -07:00
uid16.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
user.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
wait.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
workqueue.c [PATCH] re-export cancel_rearming_delayed_workqueue 2005-04-16 15:23:59 -07:00