Paul Mackerras 37d8182838 perf_counter: add an mmap method to allow userspace to read hardware counters ...

Impact: new feature giving performance improvement

This adds the ability for userspace to do an mmap on a hardware counter
fd and get access to a read-only page that contains the information
needed to translate a hardware counter value to the full 64-bit
counter value that would be returned by a read on the fd.  This is
useful on architectures that allow user programs to read the hardware
counters, such as PowerPC.

The mmap will only succeed if the counter is a hardware counter
monitoring the current process.

On my quad 2.5GHz PowerPC 970MP machine, userspace can read a counter
and translate it to the full 64-bit value in about 30ns using the
mmapped page, compared to about 830ns for the read syscall on the
counter, so this does give a significant performance improvement.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Orig-LKML-Reference: <20090323172417.297057964@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2009-04-06 09:30:26 +02:00

..

irq

Merge branch 'tracing/core-v2' into tracing-for-linus

2009-04-02 00:49:02 +02:00

power

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2009-04-03 15:24:35 -07:00

time

Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-03-26 16:05:42 -07:00

trace

Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-04-05 11:04:19 -07:00

.gitignore

…

acct.c

[CVE-2009-0029] System call wrappers part 04

2009-01-14 14:15:19 +01:00

async.c

async: remove the temporary (2.6.29) "async is off by default" code

2009-03-28 13:05:30 -07:00

audit_tree.c

audit: incorrect ref counting in audit tree tag_chunk

2009-04-05 13:48:26 -04:00

audit.c

Audit: remove spaces from audit_log_d_path

2009-04-05 13:49:04 -04:00

audit.h

fixing audit rule ordering mess, part 1

2009-01-04 15:14:41 -05:00

auditfilter.c

make the e->rule.xxx shorter in kernel auditfilter.c

2009-04-05 13:40:33 -04:00

auditsc.c

Audit: remove spaces from audit_log_d_path

2009-04-05 13:49:04 -04:00

backtracetest.c

…

bounds.c

…

capability.c

[CVE-2009-0029] System call wrappers part 04

2009-01-14 14:15:19 +01:00

cgroup_debug.c

debug cgroup: remove unneeded cgroup_lock

2009-04-02 19:04:54 -07:00

cgroup_freezer.c

freezer_cg: disable writing freezer.state of root cgroup

2008-11-12 17:17:16 -08:00

cgroup.c

memcg: fix OOM killer under memcg

2009-04-02 19:04:55 -07:00

compat.c

Allow times and time system calls to return small negative values

2009-01-06 15:59:13 -08:00

configs.c

…

cpu.c

cpumask: use set_cpu_active in init/main.c

2009-03-30 22:05:12 +10:30

cpuset.c

cpusets: prevent PF_THREAD_BOUND tasks from attaching to non-root cpusets

2009-04-02 19:04:57 -07:00

cred-internals.h

CRED: Inaugurate COW credentials

2008-11-14 10:39:23 +11:00

cred.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6

2009-01-09 13:59:25 -08:00

delayacct.c

schedstat: consolidate per-task cpu runtime stats

2008-12-18 13:54:01 +01:00

dma-coherent.c

dma-coherent: Restore dma_alloc_from_coherent() large alloc fall back policy.

2009-01-21 18:51:53 +09:00

dma.c

…

exec_domain.c

Get rid of indirect include of fs_struct.h

2009-03-31 23:00:27 -04:00

exit.c

Merge branch 'linus' into perfcounters/core-v2

2009-04-06 09:02:57 +02:00

extable.c

Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-04-05 11:04:19 -07:00

fork.c

Merge branch 'linus' into perfcounters/core-v2

2009-04-06 09:02:57 +02:00

freezer.c

freezer_cg: use thaw_process() in unfreeze_cgroup()

2008-10-30 11:38:45 -07:00

futex_compat.c

CRED: Use RCU to access another task's creds and to release a task's own creds

2008-11-14 10:39:19 +11:00

futex.c

futex: remove the pointer math from double_unlock_hb, fix

2009-03-13 10:32:07 +01:00

hrtimer.c

hrtimer: prevent negative expiry value after clock_was_set()

2009-01-30 22:35:34 +01:00

itimer.c

timers: split process wide cpu clocks/timers

2009-02-05 13:04:33 +01:00

kallsyms.c

Ksplice: Add functions for walking kallsyms symbols

2009-03-31 13:05:32 +10:30

Kconfig.freezer

…

Kconfig.hz

…

Kconfig.preempt

rcu: provide RCU options on non-preempt architectures too

2008-12-25 09:31:28 +01:00

kexec.c

kexec: vmcoreinfo_data[] can become static

2009-04-02 19:05:04 -07:00

kfifo.c

…

kgdb.c

…

kmod.c

module: create a request_module_nowait()

2009-03-31 13:05:35 +10:30

kprobes.c

kprobes: Fix locking imbalance in kretprobes

2009-03-18 12:51:16 +01:00

ksysfs.c

kernel/ksysfs.c:fix dependence on CONFIG_NET

2009-01-06 10:44:31 -08:00

kthread.c

cpumask: remove dangerous CPU_MASK_ALL_PTR, &CPU_MASK_ALL

2009-03-30 22:05:11 +10:30

latencytop.c

sched, latencytop: incorporate review feedback from Andrew Morton

2009-02-11 10:18:04 +01:00

lockdep_internals.h

lockdep: get_user_chars() redo

2009-02-14 23:28:22 +01:00

lockdep_proc.c

lockstat: warn about disabled lock debugging

2009-02-14 23:28:28 +01:00

lockdep_states.h

lockdep: move state bit definitions around

2009-02-14 23:27:59 +01:00

lockdep.c

Merge branch 'tracing/core-v2' into tracing-for-linus

2009-04-02 00:49:02 +02:00

Makefile

Merge branch 'linus' into perfcounters/core-v2

2009-04-06 09:02:57 +02:00

marker.c

markers/tracpoints: fix non-modular build

2008-11-16 09:52:03 +01:00

module.c

Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-04-05 11:04:19 -07:00

mutex-debug.c

mutex: implement adaptive spinning

2009-01-14 18:09:02 +01:00

mutex-debug.h

mutex: implement adaptive spinning

2009-01-14 18:09:02 +01:00

mutex.c

mutex: adaptive spinnning, performance tweaks

2009-01-14 19:03:54 +01:00

mutex.h

mutex: implement adaptive spinning

2009-01-14 18:09:02 +01:00

notifier.c

Merge commit 'v2.6.28-rc6' into core/debug

2008-11-26 08:22:50 +01:00

ns_cgroup.c

cgroups: relax ns_can_attach checks to allow attaching to grandchild cgroups

2009-04-02 19:04:53 -07:00

nsproxy.c

User namespaces: set of cleanups (v2)

2008-11-24 18:57:41 -05:00

panic.c

panic: clean up kernel/panic.c

2009-03-13 11:25:53 +01:00

params.c

param: fix charp parameters set via sysfs

2009-03-31 13:05:30 +10:30

perf_counter.c

perf_counter: add an mmap method to allow userspace to read hardware counters

2009-04-06 09:30:26 +02:00

pid_namespace.c

signals: zap_pid_ns_process() should use force_sig()

2009-04-02 19:04:58 -07:00

pid.c

pids: refactor vnr/nr_ns helpers to make them safe

2009-04-02 19:05:02 -07:00

pm_qos_params.c

…

posix-cpu-timers.c

posix timers: fix RLIMIT_CPU && fork()

2009-03-23 20:43:35 +01:00

posix-timers.c

[CVE-2009-0029] System call wrappers part 05

2009-01-14 14:15:20 +01:00

printk.c

Merge branch 'printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-04-05 10:23:25 -07:00

profile.c

profiling: fix broken profiling regression

2009-02-10 00:50:37 +01:00

ptrace.c

Merge branch 'core-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-04-03 17:35:06 -07:00

rcuclassic.c

rcu: Teach RCU that idle task is not quiscent state at boot

2009-02-26 04:08:14 +01:00

rcupdate.c

rcu: rcu_barrier VS cpu_hotplug: Ensure callbacks in dead cpu are migrated to online cpu

2009-03-31 00:09:37 +02:00

rcupreempt_trace.c

"Tree RCU": scalable classic RCU implementation

2008-12-18 21:56:04 +01:00

rcupreempt.c

rcu: Teach RCU that idle task is not quiscent state at boot

2009-02-26 04:08:14 +01:00

rcutorture.c

cpumask: convert rcutorture.c

2009-03-30 22:05:16 +10:30

rcutree_trace.c

"Tree RCU": scalable classic RCU implementation

2008-12-18 21:56:04 +01:00

rcutree.c

rcu: Teach RCU that idle task is not quiscent state at boot

2009-02-26 04:08:14 +01:00

relay.c

Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-04-05 11:04:19 -07:00

res_counter.c

memcg: memory cgroup resource counters for hierarchy

2009-01-08 08:31:05 -08:00

resource.c

resources: fix parameter name and kernel-doc

2009-01-15 16:39:38 -08:00

rtmutex_common.h

…

rtmutex-debug.c

…

rtmutex-debug.h

…

rtmutex-tester.c

…

rtmutex.c

…

rtmutex.h

…

rwsem.c

…

sched_clock.c

Merge branch 'tracing/core-v2' into tracing-for-linus

2009-04-02 00:49:02 +02:00

sched_cpupri.c

sched: fix section mismatch

2009-01-06 11:07:15 +01:00

sched_cpupri.h

cpumask: remove cpumask_t from core

2009-03-30 22:05:17 +10:30

sched_debug.c

sched: remove unused fields from struct rq

2009-03-24 23:16:51 +01:00

sched_fair.c

Merge branch 'sched/urgent'; commit 'v2.6.29-rc5' into sched/core

2009-02-15 21:15:16 +01:00

sched_features.h

Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-03-30 17:17:35 -07:00

sched_idletask.c

…

sched_rt.c

Merge branch 'core/percpu' into percpu-cpumask-x86-for-linus-2

2009-03-27 17:28:43 +01:00

sched_stats.h

sched: remove unused fields from struct rq

2009-03-24 23:16:51 +01:00

sched.c

perf_counter: generic context switch event

2009-04-06 09:30:15 +02:00

seccomp.c

x86-64: seccomp: fix 32/64 syscall hole

2009-03-02 15:41:30 -08:00

semaphore.c

…

signal.c

signals: SI_USER: Masquerade si_pid when crossing pid ns boundary

2009-04-02 19:04:58 -07:00

slow-work.c

Document the slow work thread pool

2009-04-03 16:42:35 +01:00

smp.c

generic-ipi: eliminate WARN_ON()s during oops/panic

2009-03-13 10:47:34 +01:00

softirq.c

Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-04-05 11:04:19 -07:00

softlockup.c

softlock: fix false panic which can occur if softlockup_thresh is reduced

2009-01-14 11:48:07 +01:00

spinlock.c

Allow rwlocks to re-enable interrupts

2009-04-02 19:05:11 -07:00

srcu.c

…

stacktrace.c

stacktrace: provide save_stack_trace_tsk() weak alias

2008-12-25 11:44:43 +01:00

stop_machine.c

cpumask: remove cpumask_t from core

2009-03-30 22:05:17 +10:30

sys_ni.c

Merge commit 'v2.6.29-rc2' into perfcounters/core

2009-01-21 16:37:27 +01:00

sys.c

Merge branch 'linus' into perfcounters/core-v2

2009-04-06 09:02:57 +02:00

sysctl_check.c

net: add ARP notify option for devices

2009-02-01 01:04:33 -08:00

sysctl.c

Make the slow work pool configurable

2009-04-03 16:42:35 +01:00

taskstats.c

cpumask: convert rest of files in kernel/

2009-01-01 10:12:28 +10:30

test_kprobes.c

kprobes: add tests for register_kprobes

2009-01-06 15:59:20 -08:00

time.c

[CVE-2009-0029] System call wrappers part 01

2009-01-14 14:15:18 +01:00

timeconst.pl

…

timer.c

Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-03-30 17:17:35 -07:00

tracepoint.c

tracepoints: dont update zero-sized tracepoint sections

2009-03-18 19:55:00 +01:00

tsacct.c

Fix fixpoint divide exception in acct_update_integrals

2009-03-09 08:13:35 -07:00

uid16.c

[CVE-2009-0029] System call wrappers part 19

2009-01-14 14:15:26 +01:00

up.c

smp_call_function_single(): be slightly less stupid, fix #2

2009-01-12 16:04:37 +01:00

user_namespace.c

Fix recursive lock in free_uid()/free_user_ns()

2009-02-27 16:26:21 -08:00

user.c

Merge branch 'master' into next

2009-03-24 10:52:46 +11:00

utsname_sysctl.c

proc_sysctl: use CONFIG_PROC_SYSCTL around ipc and utsname proc_handlers

2009-04-02 19:05:01 -07:00

utsname.c

…

wait.c

wait: prevent exclusive waiter starvation

2009-02-05 12:56:48 -08:00

workqueue.c

Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-04-05 11:04:19 -07:00