Currently the full dynticks subsystem keep the
tick alive as long as there are perf events running.

This prevents the tick from being stopped as long as features
such that the lockup detectors are running. As a temporary fix,
the lockup detector is disabled by default when full dynticks
is built but this is not a long term viable solution.

To fix this, only keep the tick alive when an event configured
with a frequency rather than a period is running on the CPU,
or when an event throttles on the CPU.

These are the only purposes of the perf tick, especially now that
the rotation of flexible events is handled from a seperate hrtimer.
The tick can be shutdown the rest of the time.
Original-patch-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-8-git-send-email-fweisbec@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This is going to be used by the full dynticks subsystem
as a finer-grained information to know when to keep and
when to stop the tick.
Original-patch-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-7-git-send-email-fweisbec@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

When an event is migrated, move the event per-cpu
accounting accordingly so that branch stack and cgroup
events work correctly on the new CPU.
Original-patch-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-6-git-send-email-fweisbec@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This way we can use the per-cpu handling seperately.
This is going to be used by to fix the event migration
code accounting.
Original-patch-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-5-git-send-email-fweisbec@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Gather all the event accounting code to a single place,
once all the prerequisites are completed. This simplifies
the refcounting.
Original-patch-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-4-git-send-email-fweisbec@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

In case of allocation failure, get_callchain_buffer() keeps the
refcount incremented for the current event.

As a result, when get_callchain_buffers() returns an error,
we must cleanup what it did by cancelling its last refcount
with a call to put_callchain_buffers().

This is a hack in order to be able to call free_event()
after that failure.

The original purpose of that was to simplify the failure
path. But this error handling is actually counter intuitive,
ugly and not very easy to follow because one expect to
see the resources used to perform a service to be cleaned
by the callee if case of failure, not by the caller.

So lets clean this up by cancelling the refcount from
get_callchain_buffer() in case of failure. And correctly free
the event accordingly in perf_event_alloc().
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-3-git-send-email-fweisbec@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

On callchain buffers allocation failure, free_event() is
called and all the accounting performed in perf_event_alloc()
for that event is cancelled.

But if the event has branch stack sampling, it is unaccounted
as well from the branch stack sampling events refcounts.

This is a bug because this accounting is performed after the
callchain buffer allocation. As a result, the branch stack sampling
events refcount can become negative.

To fix this, move the branch stack event accounting before the
callchain buffer allocation.
Reported-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1374539466-4799-2-git-send-email-fweisbec@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Due to a discussion with Adrian I had a good look at the perf_event_type record
layout and found the documentation to be somewhat unclear.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130716150907.GL23818@dyad.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

A number of parts of the kernel created their own version of this, might
as well have the sysfs core provide it instead.
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Tested-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications.  For example, the fix in
commit 5e427ec2 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out.  Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

This removes all the uses of the __cpuinit macros from C files in
the core kernel directories (kernel, init, lib, mm, and include)
that don't really have a specific maintainer.

[1] https://lkml.org/lkml/2013/5/20/589Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

It gives the following benefits:

  - only one function pointer is passed along the way

  - the 'match' function is called within output function
    and could be inlined by the compiler
Suggested-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1373388991-9711-1-git-send-email-jolsa@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Jiri managed to trigger this warning:

 [] ======================================================
 [] [ INFO: possible circular locking dependency detected ]
 [] 3.10.0+ #228 Tainted: G        W
 [] -------------------------------------------------------
 [] p/6613 is trying to acquire lock:
 []  (rcu_node_0){..-...}, at: [<ffffffff810ca797>] rcu_read_unlock_special+0xa7/0x250
 []
 [] but task is already holding lock:
 []  (&ctx->lock){-.-...}, at: [<ffffffff810f2879>] perf_lock_task_context+0xd9/0x2c0
 []
 [] which lock already depends on the new lock.
 []
 [] the existing dependency chain (in reverse order) is:
 []
 [] -> #4 (&ctx->lock){-.-...}:
 [] -> #3 (&rq->lock){-.-.-.}:
 [] -> #2 (&p->pi_lock){-.-.-.}:
 [] -> #1 (&rnp->nocb_gp_wq[1]){......}:
 [] -> #0 (rcu_node_0){..-...}:

Paul was quick to explain that due to preemptible RCU we cannot call
rcu_read_unlock() while holding scheduler (or nested) locks when part
of the read side critical section was preemptible.

Therefore solve it by making the entire RCU read side non-preemptible.

Also pull out the retry from under the non-preempt to play nice with RT.
Reported-by: NJiri Olsa <jolsa@redhat.com>
Helped-out-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

The '!ctx->is_active' check has a valid scenario, so
there's no need for the warning.

The reason is that there's a time window between the
'ctx->is_active' check in the perf_event_enable() function
and the __perf_event_enable() function having:

  - IRQs on
  - ctx->lock unlocked

where the task could be killed and 'ctx' deactivated by
perf_event_exit_task(), ending up with the warning below.

So remove the WARN_ON_ONCE() check and add comments to
explain it all.

This addresses the following warning reported by Vince Weaver:

[  324.983534] ------------[ cut here ]------------
[  324.984420] WARNING: at kernel/events/core.c:1953 __perf_event_enable+0x187/0x190()
[  324.984420] Modules linked in:
[  324.984420] CPU: 19 PID: 2715 Comm: nmi_bug_snb Not tainted 3.10.0+ #246
[  324.984420] Hardware name: Supermicro X8DTN/X8DTN, BIOS 4.6.3 01/08/2010
[  324.984420]  0000000000000009 ffff88043fce3ec8 ffffffff8160ea0b ffff88043fce3f00
[  324.984420]  ffffffff81080ff0 ffff8802314fdc00 ffff880231a8f800 ffff88043fcf7860
[  324.984420]  0000000000000286 ffff880231a8f800 ffff88043fce3f10 ffffffff8108103a
[  324.984420] Call Trace:
[  324.984420]  <IRQ>  [<ffffffff8160ea0b>] dump_stack+0x19/0x1b
[  324.984420]  [<ffffffff81080ff0>] warn_slowpath_common+0x70/0xa0
[  324.984420]  [<ffffffff8108103a>] warn_slowpath_null+0x1a/0x20
[  324.984420]  [<ffffffff81134437>] __perf_event_enable+0x187/0x190
[  324.984420]  [<ffffffff81130030>] remote_function+0x40/0x50
[  324.984420]  [<ffffffff810e51de>] generic_smp_call_function_single_interrupt+0xbe/0x130
[  324.984420]  [<ffffffff81066a47>] smp_call_function_single_interrupt+0x27/0x40
[  324.984420]  [<ffffffff8161fd2f>] call_function_single_interrupt+0x6f/0x80
[  324.984420]  <EOI>  [<ffffffff816161a1>] ? _raw_spin_unlock_irqrestore+0x41/0x70
[  324.984420]  [<ffffffff8113799d>] perf_event_exit_task+0x14d/0x210
[  324.984420]  [<ffffffff810acd04>] ? switch_task_namespaces+0x24/0x60
[  324.984420]  [<ffffffff81086946>] do_exit+0x2b6/0xa40
[  324.984420]  [<ffffffff8161615c>] ? _raw_spin_unlock_irq+0x2c/0x30
[  324.984420]  [<ffffffff81087279>] do_group_exit+0x49/0xc0
[  324.984420]  [<ffffffff81096854>] get_signal_to_deliver+0x254/0x620
[  324.984420]  [<ffffffff81043057>] do_signal+0x57/0x5a0
[  324.984420]  [<ffffffff8161a164>] ? __do_page_fault+0x2a4/0x4e0
[  324.984420]  [<ffffffff8161665c>] ? retint_restore_args+0xe/0xe
[  324.984420]  [<ffffffff816166cd>] ? retint_signal+0x11/0x84
[  324.984420]  [<ffffffff81043605>] do_notify_resume+0x65/0x80
[  324.984420]  [<ffffffff81616702>] retint_signal+0x46/0x84
[  324.984420] ---[ end trace 442ec2f04db3771a ]---
Reported-by: NVince Weaver <vincent.weaver@maine.edu>
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Suggested-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1373384651-6109-2-git-send-email-jolsa@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Currently when the child context for inherited events is
created, it's based on the pmu object of the first event
of the parent context.

This is wrong for the following scenario:

  - HW context having HW and SW event
  - HW event got removed (closed)
  - SW event stays in HW context as the only event
    and its pmu is used to clone the child context

The issue starts when the cpu context object is touched
based on the pmu context object (__get_cpu_context). In
this case the HW context will work with SW cpu context
ending up with following WARN below.

Fixing this by using parent context pmu object to clone
from child context.

Addresses the following warning reported by Vince Weaver:

[ 2716.472065] ------------[ cut here ]------------
[ 2716.476035] WARNING: at kernel/events/core.c:2122 task_ctx_sched_out+0x3c/0x)
[ 2716.476035] Modules linked in: nfsd auth_rpcgss oid_registry nfs_acl nfs locn
[ 2716.476035] CPU: 0 PID: 3164 Comm: perf_fuzzer Not tainted 3.10.0-rc4 #2
[ 2716.476035] Hardware name: AOpen   DE7000/nMCP7ALPx-DE R1.06 Oct.19.2012, BI2
[ 2716.476035]  0000000000000000 ffffffff8102e215 0000000000000000 ffff88011fc18
[ 2716.476035]  ffff8801175557f0 0000000000000000 ffff880119fda88c ffffffff810ad
[ 2716.476035]  ffff880119fda880 ffffffff810af02a 0000000000000009 ffff880117550
[ 2716.476035] Call Trace:
[ 2716.476035]  [<ffffffff8102e215>] ? warn_slowpath_common+0x5b/0x70
[ 2716.476035]  [<ffffffff810ab2bd>] ? task_ctx_sched_out+0x3c/0x5f
[ 2716.476035]  [<ffffffff810af02a>] ? perf_event_exit_task+0xbf/0x194
[ 2716.476035]  [<ffffffff81032a37>] ? do_exit+0x3e7/0x90c
[ 2716.476035]  [<ffffffff810cd5ab>] ? __do_fault+0x359/0x394
[ 2716.476035]  [<ffffffff81032fe6>] ? do_group_exit+0x66/0x98
[ 2716.476035]  [<ffffffff8103dbcd>] ? get_signal_to_deliver+0x479/0x4ad
[ 2716.476035]  [<ffffffff810ac05c>] ? __perf_event_task_sched_out+0x230/0x2d1
[ 2716.476035]  [<ffffffff8100205d>] ? do_signal+0x3c/0x432
[ 2716.476035]  [<ffffffff810abbf9>] ? ctx_sched_in+0x43/0x141
[ 2716.476035]  [<ffffffff810ac2ca>] ? perf_event_context_sched_in+0x7a/0x90
[ 2716.476035]  [<ffffffff810ac311>] ? __perf_event_task_sched_in+0x31/0x118
[ 2716.476035]  [<ffffffff81050dd9>] ? mmdrop+0xd/0x1c
[ 2716.476035]  [<ffffffff81051a39>] ? finish_task_switch+0x7d/0xa6
[ 2716.476035]  [<ffffffff81002473>] ? do_notify_resume+0x20/0x5d
[ 2716.476035]  [<ffffffff813654f5>] ? retint_signal+0x3d/0x78
[ 2716.476035] ---[ end trace 827178d8a5966c3d ]---
Reported-by: NVince Weaver <vincent.weaver@maine.edu>
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1373384651-6109-1-git-send-email-jolsa@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch fixes a serious bug in:

  14c63f17 perf: Drop sample rate when sampling is too slow

There was an misunderstanding on the API of the do_div()
macro. It returns the remainder of the division and this
was not what the function expected leading to disabling the
interrupt latency watchdog.

This patch also remove a duplicate assignment in
perf_sample_event_took().
Signed-off-by: NStephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: dave.hansen@linux.intel.com
Cc: ak@linux.intel.com
Cc: jolsa@redhat.com
Link: http://lkml.kernel.org/r/20130704223010.GA30625@quadSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch keeps track of how long perf's NMI handler is taking,
and also calculates how many samples perf can take a second.  If
the sample length times the expected max number of samples
exceeds a configurable threshold, it drops the sample rate.

This way, we don't have a runaway sampling process eating up the
CPU.

This patch can tend to drop the sample rate down to level where
perf doesn't work very well.  *BUT* the alternative is that my
system hangs because it spends all of its time handling NMIs.

I'll take a busted performance tool over an entire system that's
busted and undebuggable any day.

BTW, my suspicion is that there's still an underlying bug here.
Using the HPET instead of the TSC is definitely a contributing
factor, but I suspect there are some other things going on.
But, I can't go dig down on a bug like that with my machine
hanging all the time.
Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus@samba.org
Cc: acme@ghostprotocols.net
Cc: Dave Hansen <dave@sr71.net>
[ Prettified it a bit. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

This allows us to use pdev->name for registering a PMU device.
IMO the name is not supposed to be changed anyway.
Signed-off-by: NMischa Jonker <mjonker@synopsys.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1370339148-5566-1-git-send-email-mjonker@synopsys.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Commit 2b923c8f perf/x86: Check branch sampling priv level in generic code
was missing the check for the hypervisor (HV) priv level, so add it back.

With this patch, we get the following correct behavior:

  # echo 2 >/proc/sys/kernel/perf_event_paranoid

  $ perf record -j any,k noploop 1
  Error:
  You may not have permission to collect stats.
  Consider tweaking /proc/sys/kernel/perf_event_paranoid:
   -1 - Not paranoid at all
    0 - Disallow raw tracepoint access for unpriv
    1 - Disallow cpu events for unpriv
    2 - Disallow kernel profiling for unpriv

   $ perf record -j any,hv noploop 1
   Error:
   You may not have permission to collect stats.
   Consider tweaking /proc/sys/kernel/perf_event_paranoid:
    -1 - Not paranoid at all
     0 - Disallow raw tracepoint access for unpriv
     1 - Disallow cpu events for unpriv
     2 - Disallow kernel profiling for unpriv
Signed-off-by: NStephane Eranian <eranian@google.com>
Acked-by: NPetr Matousek <pmatouse@redhat.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130606090204.GA3725@quadSigned-off-by: NIngo Molnar <mingo@kernel.org>

Vince's fuzzer once again found holes. This time it spotted a leak in
the locked page accounting.

When an event had redirected output and its close() was the last
reference to the buffer we didn't have a vm context to undo accounting.

Change the code to destroy the buffer on the last munmap() and detach
all redirected events at that time. This provides us the right context
to undo the vm accounting.
Reported-and-tested-by: NVince Weaver <vincent.weaver@maine.edu>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130604084421.GI8923@twins.programming.kicks-ass.net
Cc: <stable@kernel.org>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Vince reported a problem found by his perf specific trinity
fuzzer.

Al noticed 2 problems with perf's mmap():

 - it has issues against fork() since we use vma->vm_mm for accounting.
 - it has an rb refcount leak on double mmap().

We fix the issues against fork() by using VM_DONTCOPY; I don't
think there's code out there that uses this; we didn't hear
about weird accounting problems/crashes. If we do need this to
work, the previously proposed VM_PINNED could make this work.

Aside from the rb reference leak spotted by Al, Vince's example
prog was indeed doing a double mmap() through the use of
perf_event_set_output().

This exposes another problem, since we now have 2 events with
one buffer, the accounting gets screwy because we account per
event. Fix this by making the buffer responsible for its own
accounting.
Reported-by: NVince Weaver <vincent.weaver@maine.edu>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/20130528085548.GA12193@twins.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch moves commit 7cc23cd6 to the generic code:

 perf/x86/intel/lbr: Demand proper privileges for PERF_SAMPLE_BRANCH_KERNEL

The check is now implemented in generic code instead of x86 specific
code. That way we do not have to repeat the test in each arch
supporting branch sampling.
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/r/20130521105337.GA2879@quadSigned-off-by: NIngo Molnar <mingo@kernel.org>

This patch adds /sys/device/xxx/perf_event_mux_interval_ms to ajust
the multiplexing interval per PMU. The unit is milliseconds. Value has
to be >= 1.

In the 4th version, we renamed the sysfs file to be more consistent
with the other /proc/sys/kernel entries for perf_events.

In the 5th version, we handle the reprogramming of the hrtimer using
hrtimer_forward_now(). That way, we sync up to new timer value quickly
(suggested by Jiri Olsa).
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/r/1364991694-5876-3-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

The current scheme of using the timer tick was fine for per-thread
events. However, it was causing bias issues in system-wide mode
(including for uncore PMUs). Event groups would not get their fair
share of runtime on the PMU. With tickless kernels, if a core is idle
there is no timer tick, and thus no event rotation (multiplexing).
However, there are events (especially uncore events) which do count
even though cores are asleep.

This patch changes the timer source for multiplexing.  It introduces a
per-PMU per-cpu hrtimer. The advantage is that even when a core goes
idle, it will come back to service the hrtimer, thus multiplexing on
system-wide events works much better.

The per-PMU implementation (suggested by PeterZ) enables adjusting the
multiplexing interval per PMU. The preferred interval is stashed into
the struct pmu. If not set, it will be forced to the default interval
value.

In order to minimize the impact of the hrtimer, it is turned on and
off on demand. When the PMU on a CPU is overcommited, the hrtimer is
activated.  It is stopped when the PMU is not overcommitted.

In order for this to work properly, we had to change the order of
initialization in start_kernel() such that hrtimer_init() is run
before perf_event_init().

The default interval in milliseconds is set to a timer tick just like
with the old code. We will provide a sysctl to tune this in another
patch.
Signed-off-by: NStephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/r/1364991694-5876-2-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

The hw breakpoint pmu 'add' function is missing the
period_left update needed for SW events.

The perf HW breakpoint events use the SW events framework
to process the overflow, so it needs to be properly initialized
in the PMU 'add' method.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Reviewed-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1367421944-19082-5-git-send-email-jolsa@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Add perf_event_aux() function to send out all types of
auxiliary events - mmap, task, comm events. For each type
there's match and output functions defined and used as
callbacks during perf_event_aux processing.

This way we can centralize the pmu/context iterating and
event matching logic. Also since lot of the code was
duplicated, this patch reduces the .text size about 2kB
on my setup:

  snipped output from 'objdump -x kernel/events/core.o'

  before:
  Idx Name          Size
    0 .text         0000d313

  after:
  Idx Name          Size
    0 .text         0000cad3
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/1367857638-27631-3-git-send-email-jolsa@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

The perf_event_task_ctx() function needs to be called with
preemption disabled, since it's checking for currently
scheduled cpu against event cpu.

We disable preemption for task related perf event context
if there's one defined, leaving up to the chance which cpu
it gets scheduled in.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/1367857638-27631-2-git-send-email-jolsa@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Provide a new helper that help full dynticks CPUs to prevent
from stopping their tick in case there are events in the local
rotation list.

This way we make sure that perf_event_task_tick() is serviced
on demand.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephane Eranian <eranian@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>

Kick the current CPU's tick by sending it a self IPI when
an event is queued on the rotation list and it is the first
element inserted. This makes sure that perf_event_task_tick()
works on full dynticks CPUs.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephane Eranian <eranian@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>

The following RCU splat indicates lack of RCU protection:

[  953.267649] ===============================
[  953.267652] [ INFO: suspicious RCU usage. ]
[  953.267657] 3.9.0-0.rc6.git2.4.fc19.ppc64p7 #1 Not tainted
[  953.267661] -------------------------------
[  953.267664] include/linux/cgroup.h:534 suspicious rcu_dereference_check() usage!
[  953.267669]
[  953.267669] other info that might help us debug this:
[  953.267669]
[  953.267675]
[  953.267675] rcu_scheduler_active = 1, debug_locks = 0
[  953.267680] 1 lock held by glxgears/1289:
[  953.267683]  #0:  (&sig->cred_guard_mutex){+.+.+.}, at: [<c00000000027f884>] .prepare_bprm_creds+0x34/0xa0
[  953.267700]
[  953.267700] stack backtrace:
[  953.267704] Call Trace:
[  953.267709] [c0000001f0d1b6e0] [c000000000016e30] .show_stack+0x130/0x200 (unreliable)
[  953.267717] [c0000001f0d1b7b0] [c0000000001267f8] .lockdep_rcu_suspicious+0x138/0x180
[  953.267724] [c0000001f0d1b840] [c0000000001d43a4] .perf_event_comm+0x4c4/0x690
[  953.267731] [c0000001f0d1b950] [c00000000027f6e4] .set_task_comm+0x84/0x1f0
[  953.267737] [c0000001f0d1b9f0] [c000000000280414] .setup_new_exec+0x94/0x220
[  953.267744] [c0000001f0d1ba70] [c0000000002f665c] .load_elf_binary+0x58c/0x19b0
...

This commit therefore adds the required RCU read-side critical
section to perf_event_comm().
Reported-by: NAdam Jackson <ajax@redhat.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: a.p.zijlstra@chello.nl
Cc: paulus@samba.org
Cc: acme@ghostprotocols.net
Link: http://lkml.kernel.org/r/20130419190124.GA8638@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
Tested-by: NGustavo Luiz Duarte <gusld@br.ibm.com>

Trinity discovered that we fail to check all 64 bits of
attr.config passed by user space, resulting to out-of-bounds
access of the perf_swevent_enabled array in
sw_perf_event_destroy().

Introduced in commit b0a873eb ("perf: Register PMU
implementations").
Signed-off-by: NTommi Rantala <tt.rantala@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: davej@redhat.com
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/1365882554-30259-1-git-send-email-tt.rantala@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Fix to return -ENOMEM in the allocation error case instead of 0
(if pmu_bus_running == 1), as done elsewhere in this function.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: a.p.zijlstra@chello.nl
Cc: paulus@samba.org
Cc: acme@ghostprotocols.net
Link: http://lkml.kernel.org/r/CAPgLHd8j_fWcgqe%3DKLWjpBj%2B%3Do0Pw6Z-SEq%3DNTPU08c2w1tngQ@mail.gmail.com
[ Tweaked the error code setting placement and the changelog. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

perf_event is one of a couple remaining cgroup controllers with broken
hierarchy support.  Converting it to support hierarchy is almost
trivial.  The only thing necessary is to consider a task belonging to
a descendant cgroup as a match.  IOW, if the cgroup of the currently
executing task (@cpuctx->cgrp) equals or is a descendant of the
event's cgroup (@event->cgrp), then the event should be enabled.

Implement hierarchy support and remove .broken_hierarchy tag along
with the incorrect comment on what needs to be done for hierarchy
support.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Stephane Eranian <eranian@google.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>

For NUL terminated string, always make sure that there's '\0' at the end.

In our case we need a return value, so still use strncpy() and
fix up the tail explicitly.

(strlcpy() returns the size, not the pointer)
Signed-off-by: NChen Gang <gang.chen@asianux.com>
Cc: a.p.zijlstra@chello.nl <a.p.zijlstra@chello.nl>
Cc: paulus@samba.org <paulus@samba.org>
Cc: acme@ghostprotocols.net <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/51623E0B.7070101@asianux.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Type of mapping was lost and made it hard for a tool
to distinguish code vs. data mmaps. Perf has the ability
to distinguish the two.

Use a bit in the header->misc bitmask to keep track of
the mmap type. If PERF_RECORD_MISC_MMAP_DATA is set then
the mapping is not executable (!VM_EXEC). If not set, then
the mapping is executable.
Signed-off-by: NStephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: ak@linux.intel.com
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: namhyung.kim@lge.com
Link: http://lkml.kernel.org/r/1359040242-8269-16-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

This patch adds PERF_SAMPLE_DATA_SRC.

PERF_SAMPLE_DATA_SRC collects the data source, i.e., where
did the data associated with the sampled instruction
come from. Information is stored in a perf_mem_data_src
structure. It contains opcode, mem level, tlb, snoop,
lock information, subject to availability in hardware.
Signed-off-by: NStephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: ak@linux.intel.com
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: namhyung.kim@lge.com
Link: http://lkml.kernel.org/r/1359040242-8269-8-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

For some events it's useful to weight sample with a hardware
provided number. This expresses how expensive the action the
sample represent was.  This allows the profiler to scale
the samples to be more informative to the programmer.

There is already the period which is used similarly, but it
means something different, so I chose to not overload it.
Instead a new sample type for WEIGHT is added.

Can be used for multiple things. Initially it is used for TSX
abort costs and profiling by memory latencies (so to make
expensive load appear higher up in the histograms). The concept
is quite generic and can be extended to many other kinds of
events or architectures, as long as the hardware provides
suitable auxillary values. In principle it could be also used
for software tracepoints.

This adds the generic glue. A new optional sample format for a
64-bit weight value.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NStephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: namhyung.kim@lge.com
Link: http://lkml.kernel.org/r/1359040242-8269-5-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

It's a per-cpu data structure but missed the __percpu annotation.
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Link: http://lkml.kernel.org/r/1363600594-11453-1-git-send-email-namhyung@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

perf_event_task_event() iterates pmu list and generate events
for each eligible pmu context.  But if task_event has task_ctx
like in EXIT it'll generate events even though the pmu doesn't
have an eligible one. Fix it by moving the code to proper
places.

Before this patch:

  $ perf record -n true
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.006 MB perf.data (~248 samples) ]

  $ perf report -D | tail
  Aggregated stats:
             TOTAL events:         73
              MMAP events:         67
              COMM events:          2
              EXIT events:          4
  cycles stats:
             TOTAL events:         73
              MMAP events:         67
              COMM events:          2
              EXIT events:          4

After this patch:

  $ perf report -D | tail
  Aggregated stats:
             TOTAL events:         70
              MMAP events:         67
              COMM events:          2
              EXIT events:          1
  cycles stats:
             TOTAL events:         70
              MMAP events:         67
              COMM events:          2
              EXIT events:          1
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1363332433-7637-1-git-send-email-namhyung@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

When cpu/task clock events are initialized, their sampling
frequencies are converted to have a fixed value.  However it
missed to update the hwc->last_period which was set to 1 for
initial sampling frequency calibration.

Because this hwc->last_period value is used as a period in
perf_swevent_ hrtime(), every recorded sample will have an
incorrected period of 1.

  $ perf record -e task-clock noploop 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.158 MB perf.data (~6919 samples) ]

  $ perf report -n --show-total-period  --stdio
  # Samples: 4K of event 'task-clock'
  # Event count (approx.): 4000
  #
  # Overhead       Samples        Period  Command  Shared Object              Symbol
  # ........  ............  ............  .......  .............  ..................
  #
      99.95%          3998          3998  noploop  noploop        [.] main
       0.03%             1             1  noploop  libc-2.15.so   [.] init_cacheinfo
       0.03%             1             1  noploop  ld-2.15.so     [.] open_verify

Note that it doesn't affect the non-sampling event so that the
perf stat still gets correct value with or without this patch.

  $ perf stat -e task-clock noploop 1

   Performance counter stats for 'noploop 1':

         1000.272525 task-clock                #    1.000 CPUs utilized

         1.000560605 seconds time elapsed
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1363574507-18808-1-git-send-email-namhyung@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Move struct perf_cgroup_info and perf_cgroup to
kernel/perf/core.c, and then we can remove include of cgroup.h.
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/513568A0.6020804@huawei.comSigned-off-by: NIngo Molnar <mingo@kernel.org>