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Peter Zijlstra 0f5a260128 perf: Avoid a useless pmu_disable() in the perf-tick 
Gleb writes:

 > Currently pmu is disabled and re-enabled on each timer interrupt even
 > when no rotation or frequency adjustment is needed. On Intel CPU this
 > results in two writes into PERF_GLOBAL_CTRL MSR per tick. On bare metal
 > it does not cause significant slowdown, but when running perf in a virtual
 > machine it leads to 20% slowdown on my machine.

Cure this by keeping a perf_event_context::nr_freq counter that counts the
number of active events that require frequency adjustments and use this in a
similar fashion to the already existing nr_events != nr_active test in
perf_rotate_context().

By being able to exclude both rotation and frequency adjustments a-priory for
the common case we can avoid the otherwise superfluous PMU disable.

Suggested-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-515yhoatehd3gza7we9fapaa@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-06 08:33:52 +01:00
..
debug
Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
2011-11-06 19:44:47 -08:00
events
perf: Avoid a useless pmu_disable() in the perf-tick
2011-12-06 08:33:52 +01:00
gcov
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irq
Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
2011-11-06 19:44:47 -08:00
power
PM / QoS: Set cpu_dma_pm_qos->name
2011-11-07 23:02:24 +01:00
time
kernel: Fix files explicitly needing EXPORT_SYMBOL infrastructure
2011-10-31 19:30:05 -04:00
trace
Merge branch 'perf/urgent' into perf/core
2011-12-06 06:43:49 +01:00
.gitignore
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acct.c
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async.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
audit_tree.c
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audit_watch.c
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audit.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
audit.h
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auditfilter.c
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auditsc.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
backtracetest.c
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bounds.c
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capability.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
cgroup_freezer.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
cgroup.c
memcg: replace ss->id_lock with a rwlock
2011-11-02 16:07:03 -07:00
compat.c
kernel: Fix files explicitly needing EXPORT_SYMBOL infrastructure
2011-10-31 19:30:05 -04:00
configs.c
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cpu_pm.c
cpu_pm: call notifiers during suspend
2011-09-23 12:05:29 +05:30
cpu.c
Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
2011-11-06 19:44:47 -08:00
cpuset.c
Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
2011-11-06 19:44:47 -08:00
crash_dump.c
Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
2011-11-06 19:44:47 -08:00
cred.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
delayacct.c
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dma.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
elfcore.c
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exec_domain.c
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exit.c
oom: remove oom_disable_count
2011-10-31 17:30:45 -07:00
extable.c
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fork.c
Merge branch 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux
2011-11-06 19:02:23 -08:00
freezer.c
Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
2011-11-06 19:44:47 -08:00
futex_compat.c
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futex.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
groups.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
hrtimer.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
hung_task.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
irq_work.c
kernel: fix two implicit header assumptions in irq_work.c
2011-10-31 09:20:12 -04:00
itimer.c
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jump_label.c
jump_label: jump_label_inc may return before the code is patched
2011-12-05 13:28:46 -05:00
kallsyms.c
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Kconfig.freezer
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Kconfig.hz
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Kconfig.locks
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Kconfig.preempt
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kexec.c
[S390] kdump: Add infrastructure for unmapping crashkernel memory
2011-10-30 15:16:42 +01:00
kfifo.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
kmod.c
kmod: prevent kmod_loop_msg overflow in __request_module()
2011-10-26 13:10:39 +10:30
kprobes.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
ksysfs.c
kernel: ksysfs.c is implicitly using stat.h
2011-10-31 09:20:13 -04:00
kthread.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
latencytop.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
lockdep_internals.h
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lockdep_proc.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
lockdep_states.h
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lockdep.c
Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/core
2011-11-11 08:19:37 +01:00
Makefile
Merge branch 'devel-stable' of http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm
2011-10-28 12:02:27 -07:00
module.c
Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
2011-11-06 19:44:47 -08:00
mutex-debug.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
mutex-debug.h
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mutex.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
mutex.h
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notifier.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
nsproxy.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
padata.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
panic.c
module,bug: Add TAINT_OOT_MODULE flag for modules not built in-tree
2011-11-07 07:54:42 +10:30
params.c
kernel: params.c needs module.h not moduleparam.h
2011-10-31 09:20:13 -04:00
pid_namespace.c
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pid.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
posix-cpu-timers.c
Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2011-10-26 16:17:32 +02:00
posix-timers.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
printk.c
printk: remove bounds checking for log_prefix
2011-10-31 17:30:53 -07:00
profile.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
ptrace.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
range.c
range: fix bogus misuse of module.h to get printk()
2011-10-31 09:20:11 -04:00
rcu.h
rcu: Add grace-period, quiescent-state, and call_rcu trace events
2011-09-28 21:38:21 -07:00
rcupdate.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
rcutiny_plugin.h
kernel: fix up module header handling in rcutiny files
2011-10-31 09:20:13 -04:00
rcutiny.c
kernel: fix up module header handling in rcutiny files
2011-10-31 09:20:13 -04:00
rcutorture.c
rcu: Make rcu_torture_boost() exit loops at end of test
2011-09-28 21:38:46 -07:00
rcutree_plugin.h
rcu: Remove rcu_needs_cpu_flush() to avoid false quiescent states
2011-09-28 21:38:48 -07:00
rcutree_trace.c
rcu: Simplify quiescent-state accounting
2011-09-28 21:38:22 -07:00
rcutree.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
rcutree.h
rcu: Remove rcu_needs_cpu_flush() to avoid false quiescent states
2011-09-28 21:38:48 -07:00
relay.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
res_counter.c
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resource.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
rtmutex_common.h
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rtmutex-debug.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
rtmutex-debug.h
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rtmutex-tester.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
rtmutex.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
rtmutex.h
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rwsem.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
sched_autogroup.c
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sched_autogroup.h
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sched_clock.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
sched_cpupri.c
sched/cpupri: Remove cpupri->pri_active
2011-08-14 12:01:11 +02:00
sched_cpupri.h
sched/cpupri: Remove cpupri->pri_active
2011-08-14 12:01:11 +02:00
sched_debug.c
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sched_fair.c
sched: Wrap scheduler p->cpus_allowed access
2011-10-06 12:46:56 +02:00
sched_features.h
sched: Kill WAKEUP_PREEMPT
2011-08-14 12:00:41 +02:00
sched_idletask.c
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sched_rt.c
sched: Warn on rt throttling
2011-10-06 12:47:04 +02:00
sched_stats.h
locking, sched: Annotate thread_group_cputimer as raw
2011-09-13 11:11:55 +02:00
sched_stoptask.c
sched: Implement hierarchical task accounting for SCHED_OTHER
2011-08-14 12:01:13 +02:00
sched.c
Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
2011-11-06 17:12:03 -08:00
seccomp.c
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semaphore.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
signal.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
smp.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
softirq.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
spinlock.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
srcu.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
stacktrace.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
stop_machine.c
Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
2011-11-06 19:44:47 -08:00
sys_ni.c
Cross Memory Attach
2011-10-31 17:30:44 -07:00
sys.c
Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
2011-11-06 19:44:47 -08:00
sysctl_binary.c
ipv4: NET_IPV4_ROUTE_GC_INTERVAL removal
2011-10-03 14:13:01 -04:00
sysctl_check.c
xfs: remove subdirectories
2011-08-12 16:21:35 -05:00
sysctl.c
Merge branch 'akpm' (Andrew's incoming)
2011-10-31 17:46:07 -07:00
taskstats.c
Make TASKSTATS require root access
2011-09-19 17:04:37 -07:00
test_kprobes.c
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time.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
timeconst.pl
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timer.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
tracepoint.c
Tracepoint: Dissociate from module mutex
2011-08-10 20:38:14 -04:00
tsacct.c
Make taskstats round statistics down to nearest 1k bytes/events
2011-09-19 17:10:57 -07:00
uid16.c
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up.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
user_namespace.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
user-return-notifier.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
user.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
utsname_sysctl.c
Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
2011-11-06 19:44:47 -08:00
utsname.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
wait.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00
watchdog.c
watchdog: move watchdog_*_all_cpus under CONFIG_SYSCTL
2011-10-31 17:30:53 -07:00
workqueue_sched.h
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workqueue.c
kernel: Map most files to use export.h instead of module.h
2011-10-31 09:20:12 -04:00