Woodruff, Richard 001474491f nohz: suppress needless timer reprogramming ... In my device I get many interrupts from a high speed USB device in a very short period of time. The system spends a lot of time reprogramming the hardware timer which is in a slower timing domain as compared to the CPU. This results in the CPU spending a huge amount of time waiting for the timer posting to be done. All of this reprogramming is useless as the wake up time has not changed. As measured using ETM trace this drops my reprogramming penalty from almost 60% CPU load down to 15% during high interrupt rate. I can send traces to show this. Suppress setting of duplicate timer event when timer already stopped. Timer programming can be very costly and can result in long cpu stall/wait times. [akpm@linux-foundation.org: coding-style fixes] [tglx@linutronix.de: move the check to the right place and avoid raising the softirq for nothing] Signed-off-by: Richard Woodruff <r-woodruff2@ti.com> Cc: johnstul@us.ibm.com Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>		2008-12-12 16:55:31 +01:00
..
irq	genirq: __irq_set_trigger: change pr_warning to pr_debug	2008-11-13 11:59:48 +01:00
power	[PATCH] kill obsolete temporary comment in swsusp_close()	2008-12-04 04:22:54 -05:00
time	nohz: suppress needless timer reprogramming	2008-12-12 16:55:31 +01:00
trace	ftrace: prevent recursion	2008-11-27 10:11:53 +01:00
.gitignore
acct.c	tty: Fix abusers of current->sighand->tty	2008-10-13 09:51:42 -07:00
audit_tree.c	Fix inotify watch removal/umount races	2008-11-15 12:26:44 -08:00
audit.c	[PATCH] fix broken timestamps in AVC generated by kernel threads	2008-12-09 02:27:41 -05:00
audit.h
auditfilter.c	Fix inotify watch removal/umount races	2008-11-15 12:26:44 -08:00
auditsc.c	[PATCH] fix broken timestamps in AVC generated by kernel threads	2008-12-09 02:27:41 -05:00
backtracetest.c	backtrace: replace timer with tasklet + completions	2008-06-27 18:09:16 +02:00
bounds.c
capability.c	security: Fix setting of PF_SUPERPRIV by __capable()	2008-08-14 22:59:43 +10:00
cgroup_debug.c	cgroups: fix probable race with put_css_set[_taskexit] and find_css_set	2008-10-20 08:52:38 -07:00
cgroup_freezer.c	freezer_cg: disable writing freezer.state of root cgroup	2008-11-12 17:17:16 -08:00
cgroup.c	cgroups: fix a serious bug in cgroupstats	2008-11-19 18:50:00 -08:00
compat.c	Merge branches 'timers/clocksource', 'timers/hrtimers', 'timers/nohz', 'timers/ntp', 'timers/posixtimers' and 'timers/debug' into v28-timers-for-linus	2008-10-20 13:14:06 +02:00
configs.c	kernel/configs.c: remove useless comments	2008-10-20 08:52:34 -07:00
cpu.c	cpuinit fixes in kernel/*	2008-11-30 10:03:37 -08:00
cpuset.c	sched, cpusets: fix warning in kernel/cpuset.c	2008-11-29 20:39:29 +01:00
delayacct.c	per-task-delay-accounting: update taskstats for memory reclaim delay	2008-07-25 10:53:47 -07:00
dma-coherent.c	dma-coherent: export dma_[alloc|release]_from_coherent methods	2008-08-22 08:34:53 +02:00
dma.c	kernel/dma.c: remove a CVS keyword	2008-10-16 11:21:30 -07:00
exec_domain.c	proc: move /proc/execdomains to kernel/exec_domain.c	2008-10-23 14:30:41 +04:00
exit.c	Move "exit_robust_list" into mm_release()	2008-11-15 10:20:36 -08:00
extable.c
fork.c	fix mapping_writably_mapped()	2008-12-10 14:40:45 -08:00
freezer.c	freezer_cg: use thaw_process() in unfreeze_cgroup()	2008-10-30 11:38:45 -07:00
futex_compat.c
futex.c	hrtimer: make the futex() system call use the per process slack value	2008-09-11 07:17:00 -07:00
hrtimer.c	hrtimer: clean up unused callback modes	2008-11-12 09:54:40 +01:00
itimer.c	timers: fix itimer/many thread hang	2008-09-14 16:25:35 +02:00
kallsyms.c	sprint_symbol(): use less stack	2008-11-19 18:49:58 -08:00
Kconfig.freezer	container freezer: implement freezer cgroup subsystem	2008-10-20 08:52:34 -07:00
Kconfig.hz	sched: fix SCHED_HRTICK dependency	2008-07-28 14:37:38 +02:00
Kconfig.preempt
kexec.c	kexec: fix crash_save_vmcoreinfo_init build problem	2008-10-20 15:28:50 -07:00
kfifo.c
kgdb.c	kgdb: call touch_softlockup_watchdog on resume	2008-10-06 13:50:59 -05:00
kmod.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus	2008-10-16 12:38:34 -07:00
kprobes.c	kernel/kprobes.c: don't pad kretprobe_table_locks[] on uniprocessor builds	2008-11-12 17:17:17 -08:00
ksysfs.c	profiling: dynamically enable readprofile at runtime	2008-10-16 11:21:31 -07:00
kthread.c	Merge branch 'tracing-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2008-10-20 13:35:07 -07:00
latencytop.c	KSYM_SYMBOL_LEN fixes	2008-12-10 08:01:54 -08:00
lockdep_internals.h	lockdep: build fix	2008-08-13 12:55:10 +02:00
lockdep_proc.c	lockstat: fix numerical output rounding error	2008-08-26 10:37:46 +02:00
lockdep.c	lockdep: consistent alignement for lockdep info	2008-11-21 08:59:40 +01:00
Makefile	Remove -mno-spe flags as they dont belong	2008-11-17 13:24:35 -08:00
marker.c	markers: bit-field is not thread-safe nor smp-safe	2008-10-14 10:38:45 +02:00
module.c	Merge branch 'proc' of git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc	2008-10-23 12:04:37 -07:00
mutex-debug.c	mutex-debug: check mutex magic before owner	2008-05-16 16:53:35 +02:00
mutex-debug.h
mutex.c	locking: fix mutex @key parameter kernel-doc notation	2008-07-28 18:12:36 +02:00
mutex.h
notifier.c	ftrace: ignore functions that cannot be kprobe-ed	2008-10-14 10:34:22 +02:00
ns_cgroup.c	cgroup_clone: use pid of newly created task for new cgroup	2008-07-25 10:53:37 -07:00
nsproxy.c	removed unused #include <linux/version.h>'s	2008-08-23 12:14:12 -07:00
panic.c	taint: add missing comment	2008-12-01 19:55:24 -08:00
params.c	Fix compile warning in kernel/params.c	2008-10-23 12:09:00 -07:00
pid_namespace.c	pid_ns: (BUG 11391) change ->child_reaper when init->group_leader exits	2008-09-02 19:21:38 -07:00
pid.c	pidns: remove now unused find_pid function.	2008-07-25 10:53:45 -07:00
pm_qos_params.c	pm_qos_requirement might sleep	2008-09-02 19:21:40 -07:00
posix-cpu-timers.c	posix-cpu-timers: fix clock_gettime with CLOCK_PROCESS_CPUTIME_ID	2008-11-24 16:41:40 +01:00
posix-timers.c	Merge branch 'timers/range-hrtimers' into v28-range-hrtimers-for-linus-v2	2008-10-22 09:48:06 +02:00
printk.c	printk: remove unused code from kernel/printk.c	2008-10-23 21:54:29 +02:00
profile.c	cpuinit fixes in kernel/*	2008-11-30 10:03:37 -08:00
ptrace.c	remove __ARCH_WANT_COMPAT_SYS_PTRACE	2008-11-30 11:00:15 -08:00
rcuclassic.c	rcu: RCU-based detection of stalled CPUs for Classic RCU, fix	2008-10-03 10:41:00 +02:00
rcupdate.c	rcupdate: fix bug of rcu_barrier*()	2008-10-21 15:59:53 +02:00
rcupreempt_trace.c	rcu: trace fix possible mem-leak	2008-08-15 17:54:40 +02:00
rcupreempt.c	byteorder: remove direct includes of linux/byteorder/swab[b].h	2008-10-20 08:52:40 -07:00
rcutorture.c	byteorder: remove direct includes of linux/byteorder/swab[b].h	2008-10-20 12:51:53 -07:00
relay.c	relayfs: fix infinite loop with splice()	2008-12-10 08:01:52 -08:00
res_counter.c	cgroup files: convert res_counter_write() to be a cgroups write_string() handler	2008-07-25 10:53:36 -07:00
resource.c	reserve_region_with_split: Fix GFP_KERNEL usage under spinlock	2008-11-01 09:53:58 -07:00
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c	sysdev: Pass the attribute to the low level sysdev show/store function	2008-07-21 21:55:02 -07:00
rtmutex.c	hrtimer: convert kernel/* to the new hrtimer apis	2008-09-05 21:35:13 -07:00
rtmutex.h
rwsem.c
sched_clock.c	sched_clock: prevent scd->clock from moving backwards	2008-10-10 11:17:04 +02:00
sched_cpupri.c	sched: use a 2-d bitmap for searching lowest-pri CPU	2008-06-06 15:19:28 +02:00
sched_cpupri.h	sched: fix the cpuprio count really	2008-06-06 15:19:44 +02:00
sched_debug.c	sched: fix kernel warning on /proc/sched_debug access	2008-11-16 08:07:15 +01:00
sched_fair.c	sched: release buddies on yield	2008-11-11 11:57:22 +01:00
sched_features.h	sched: backward looking buddy	2008-11-05 10:30:14 +01:00
sched_idletask.c	sched: add CONFIG_SMP consistency	2008-10-22 10:01:52 +02:00
sched_rt.c	Merge commit 'v2.6.28-rc1' into sched/urgent	2008-10-24 12:48:46 +02:00
sched_stats.h	sched, signals: fix the racy usage of ->signal in account_group_xxx/run_posix_cpu_timers	2008-11-17 16:49:35 +01:00
sched.c	sched: CPU remove deadlock fix	2008-12-09 19:27:03 +01:00
seccomp.c
semaphore.c	semaphore: __down_common: use signal_pending_state()	2008-08-05 14:33:47 -07:00
signal.c	'kill sig -1' must only apply to caller's namespace	2008-10-30 11:38:46 -07:00
smp.c	generic-ipi: fix the smp_mb() placement	2008-11-06 08:41:56 +01:00
softirq.c	irq: call __irq_enter() before calling the tick_idle_check	2008-11-10 22:36:39 +01:00
softlockup.c	check_hung_task(): unsigned sysctl_hung_task_warnings cannot be less than 0	2008-12-03 10:11:51 +01:00
spinlock.c	lockdep: spin_lock_nest_lock(), checkpatch fixes	2008-08-13 13:56:51 +02:00
srcu.c
stacktrace.c	stacktrace: fix modular build, export print_stack_trace and save_stack_trace	2008-06-30 09:20:55 +02:00
stop_machine.c	stop_machine: fix race with return value (fixes Bug #11989)	2008-11-16 15:09:52 -08:00
sys_ni.c	reintroduce accept4	2008-11-19 18:49:57 -08:00
sys.c	Merge branch 'timers/range-hrtimers' into v28-range-hrtimers-for-linus-v2	2008-10-22 09:48:06 +02:00
sysctl_check.c	sysctl: check for bogus modes	2008-07-25 10:53:45 -07:00
sysctl.c	epoll: introduce resource usage limits	2008-12-01 19:55:24 -08:00
taskstats.c	taskstats: remove initialization of static per-cpu variable	2008-07-25 10:53:47 -07:00
test_kprobes.c
time.c	select: add a timespec_add_safe() function	2008-09-05 21:34:57 -07:00
timeconst.pl
timer.c	Add round_jiffies_up and related routines	2008-11-06 08:42:48 +01:00
tracepoint.c	tracepoint: check if the probe has been registered	2008-10-27 16:45:46 +01:00
tsacct.c	task IO accounting: move all IO statistics in struct task_io_accounting	2008-07-27 16:12:28 -07:00
uid16.c
user_namespace.c	removed unused #include <linux/version.h>'s	2008-08-23 12:14:12 -07:00
user.c	sched: rt-bandwidth for user grouping interface	2008-08-19 13:10:09 +02:00
utsname_sysctl.c	sysctl: simplify ->strategy	2008-10-16 11:21:47 -07:00
utsname.c	removed unused #include <linux/version.h>'s	2008-08-23 12:14:12 -07:00
wait.c	wait: kill is_sync_wait()	2008-10-16 11:21:31 -07:00
workqueue.c	cpumask: introduce new API, without changing anything	2008-11-06 09:05:33 +01:00