linux-toradex.git/include/linux/perf_event.h, branch v2.6.35.4

perf_events: Fix races in group composition

2010-05-31T06:46:09+00:00

Group siblings don't pin each-other or the parent, so when we destroy
events we must make sure to clean up all cross referencing pointers.

In particular, for destruction of a group leader we must be able to
find all its siblings and remove their reference to it.

This means that detaching an event from its context must not detach it
from the group, otherwise we can end up failing to clear all pointers.

Solve this by clearly separating the attachment to a context and
attachment to a group, and keep the group composed until we destroy
the events.

Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

perf_events: Fix races and clean up perf_event and perf_mmap_data interaction

2010-05-31T06:46:08+00:00

In order to move toward separate buffer objects, rework the whole
perf_mmap_data construct to be a more self-sufficient entity, one
with its own lifetime rules.

This greatly sanitizes the whole output redirection code, which
was riddled with bugs and races.

Signed-off-by: Peter Zijlstra 
Cc: 
LKML-Reference: 
Signed-off-by: Ingo Molnar

perf: Remove more code from the fastpath

2010-05-21T09:37:59+00:00

Sanity checks cost instructions.

Signed-off-by: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Frederic Weisbecker 
Cc: Paul Mackerras 
Cc: Mike Galbraith 
Cc: Steven Rostedt 
LKML-Reference: <20100521090710.852926930@chello.nl>
Signed-off-by: Ingo Molnar

perf: Optimize the !vmalloc backed buffer

2010-05-21T09:37:59+00:00

Reduce code and data by using the knowledge that for
!PERF_USE_VMALLOC data_order is always 0.

Signed-off-by: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Frederic Weisbecker 
Cc: Paul Mackerras 
Cc: Mike Galbraith 
Cc: Steven Rostedt 
LKML-Reference: <20100521090710.795019386@chello.nl>
Signed-off-by: Ingo Molnar

perf: Optimize perf_output_copy()

2010-05-21T09:37:59+00:00

Reduce the clutter in perf_output_copy() by keeping
an interator in perf_output_handle.

Signed-off-by: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Frederic Weisbecker 
Cc: Paul Mackerras 
Cc: Mike Galbraith 
Cc: Steven Rostedt 
LKML-Reference: <20100521090710.742809176@chello.nl>
Signed-off-by: Ingo Molnar

perf: Fix wakeup storm for RO mmap()s

2010-05-21T09:37:58+00:00

RO mmap()s don't update the tail pointer, so
comparing against it for determining the written data
size doesn't really do any good.

Keep track of when we last did a wakeup, and compare
against that.

Signed-off-by: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Frederic Weisbecker 
Cc: Paul Mackerras 
Cc: Mike Galbraith 
Cc: Steven Rostedt 
LKML-Reference: <20100521090710.684479310@chello.nl>
Signed-off-by: Ingo Molnar

perf, trace: Optimize tracepoints by using per-tracepoint-per-cpu hlist to track events

2010-05-21T09:37:56+00:00

Avoid the swevent hash-table by using per-tracepoint
hlists.

Also, avoid conditionals on the fast path by ordering
with probe unregister so that we should never get on
the callback path without the data being there.

Signed-off-by: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Frederic Weisbecker 
Cc: Paul Mackerras 
Cc: Mike Galbraith 
Cc: Steven Rostedt 
LKML-Reference: <20100521090710.473188012@chello.nl>
Signed-off-by: Ingo Molnar

perf: Optimize perf_output_*() by avoiding local_xchg()

2010-05-18T16:35:49+00:00

Since the x86 XCHG ins implies LOCK, avoid the use by
using a sequence count instead.

Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

perf: Optimize the hotpath by converting the perf output buffer to local_t

2010-05-18T16:35:49+00:00

Since there is now only a single writer, we can use
local_t instead and avoid all these pesky LOCK insn.

Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

perf: Optimize the perf_output() path by removing IRQ-disables

2010-05-18T16:35:48+00:00

Since we can now assume there is only a single writer
to each buffer, we can remove per-cpu lock thingy and
use a simply nest-count to the same effect.

This removes the need to disable IRQs.

Signed-off-by: Peter Zijlstra 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Arnaldo Carvalho de Melo 
Cc: Frederic Weisbecker 
LKML-Reference: 
Signed-off-by: Ingo Molnar