Special events such as task or context switches are marked with an
escape code in the cpu buffer followed by an event code or a task
identifier. There is one escape code per event. To make escape
sequences also available for data samples the internal cpu buffer
format must be changed. The current implementation does not allow the
extension of event codes since this would lead to collisions with the
task identifiers. To avoid this, this patch introduces an event mask
that allows the storage of multiple events with one escape code. Now,
task identifiers are stored in the data section of the sample. The
implementation also allows the usage of custom data in a sample. As a
side effect the new code is much more readable and easier to
understand.
Signed-off-by: Robert Richter <robert.richter@amd.com>

This implements the support of samples with attached data.
Signed-off-by: Robert Richter <robert.richter@amd.com>

This function prepares the cpu buffer to write a sample.

Struct op_entry is used during operations on the ring buffer while
struct op_sample contains the data that is stored in the ring
buffer. Struct entry can be uninitialized. The function reserves a
data array that is specified by size. Use op_cpu_buffer_write_commit()
after preparing the sample. In case of errors a null pointer is
returned, otherwise the pointer to the sample.
Signed-off-by: Robert Richter <robert.richter@amd.com>

This unifies usage of variable names within oprofile.
Signed-off-by: Robert Richter <robert.richter@amd.com>

Rename the fucntion to op_add_sample() since there is a collision with
another one with the same name in buffer_sync.c.
Signed-off-by: Robert Richter <robert.richter@amd.com>

This patch renames ibs_allowed to has_ibs. Varible name fits better
now.
Signed-off-by: Robert Richter <robert.richter@amd.com>

Signed-off-by: Robert Richter <robert.richter@amd.com>

This code is broken since a TRACE_BEGIN_CODE is never sent to the
daemon. The data becomes corrupt since the backtrace is interpreted as
ibs sample.
Signed-off-by: Robert Richter <robert.richter@amd.com>

Signed-off-by: Robert Richter <robert.richter@amd.com>

Signed-off-by: Robert Richter <robert.richter@amd.com>

Signed-off-by: Robert Richter <robert.richter@amd.com>

Signed-off-by: Robert Richter <robert.richter@amd.com>

This patch removes the unused return parameter in
oprofile_begin_trace(). Also, oprofile_begin_trace() and
oprofile_end_trace() are inline now.
Signed-off-by: Robert Richter <robert.richter@amd.com>

Make code more readable. No functional changes.
Signed-off-by: Robert Richter <robert.richter@amd.com>

This patch removes add_us_sample() and simplifies add_sample(). Code
is much more readable now.
Signed-off-by: Robert Richter <robert.richter@amd.com>

This patch adds the inline function __oprofile_add_ext_sample() to
cpu_buffer.c and thus reduces overhead when calling
oprofile_add_sample().
Signed-off-by: Robert Richter <robert.richter@amd.com>

Reordering code to keep alloc/free functions together.
Signed-off-by: Robert Richter <robert.richter@amd.com>

This patch fixes the PCI device use count for AMD northbridge
devices. In case of an IBS LVT initialization failure, the PCI device
is released now by calling pci_dev_put().

If there are no initialization errors, the devices are released in
pci_get_device() while iterating.
Signed-off-by: Robert Richter <robert.richter@amd.com>

This patch moves ring buffer inline functions to cpu_buffer.c.

Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>

This patch renames cpu buffer functions to something more oprofile
specific names. Functions will be moved to the global name space.

Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>

This patch renames kernel-wide identifiers to something more oprofile
specific names.

Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>

Impact: build fix

OProfile now depends on the ring buffer infrastructure:

 arch/x86/oprofile/built-in.o: In function `oprofile_add_ibs_sample':
 : undefined reference to `ring_buffer_unlock_commit'

Select TRACING and RING_BUFFER when oprofile is enabled.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

I added EXPORT_SYMBOL_GPLs for all functions part of the API
(ring_buffer.h). This is required since oprofile is using the ring
buffer and the compilation as modules would fail otherwise.
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

The number of lost samples could be greater than the number of
received samples. This patches fixes this. The implementation
introduces return values for add_sample() and add_code().
Signed-off-by: Robert Richter <robert.richter@amd.com>

This function is no longer available after the port to the new ring
buffer. Its removal can lead to incomplete sampling sequences since
IBS samples and backtraces are transfered in multiple samples. Due to
a full buffer, samples could be lost any time. The userspace daemon
has to live with such incomplete sampling sequences as long as the
data within one sample is consistent.

This will be fixed by changing the internal buffer data there all data
of one IBS sample or a backtrace is packed in a single ring buffer
entry. This is possible since the new ring buffer supports variable
data size.
Signed-off-by: Robert Richter <robert.richter@amd.com>

This patch replaces the current oprofile cpu buffer implementation
with the ring buffer provided by the tracing framework. The motivation
here is to leave the pain of implementing ring buffers to others. Oh,
no, there are more advantages. Main reason is the support of different
sample sizes that could be stored in the buffer. Use cases for this
are IBS and Cell spu profiling. Using the new ring buffer ensures
valid and complete samples and allows copying the cpu buffer stateless
without knowing its content. Second it will use generic kernel API and
also reduce code size. And hopefully, there are less bugs.

Since the new tracing ring buffer implementation uses spin locks to
protect the buffer during read/write access, it is difficult to use
the buffer in an NMI handler. In this case, writing to the buffer by
the NMI handler (x86) could occur also during critical sections when
reading the buffer. To avoid this, there are 2 buffers for independent
read and write access. Read access is in process context only, write
access only in the NMI handler. If the read buffer runs empty, both
buffers are swapped atomically. There is potentially a small window
during swapping where the buffers are disabled and samples could be
lost.

Using 2 buffers is a little bit overhead, but the solution is clear
and does not require changes in the ring buffer implementation. It can
be changed to a single buffer solution when the ring buffer access is
implemented as non-locking atomic code.

The new buffer requires more size to store the same amount of samples
because each sample includes an u32 header. Also, there is more code
to execute for buffer access. Nonetheless, the buffer implementation
is proven in the ftrace environment and worth to use also in oprofile.

Patches that changes the internal IBS buffer usage will follow.

Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>

These functions are not yet in ring_buffer.h though they seems to be
part of the API.

Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>

This is in preparation for changes in the cpu buffer implementation.
Signed-off-by: Robert Richter <robert.richter@amd.com>

This is in preparation for changes in the cpu buffer implementation.
Signed-off-by: Robert Richter <robert.richter@amd.com>

This is in preparation for changes in the cpu buffer implementation.
Signed-off-by: Robert Richter <robert.richter@amd.com>

This is in preparation for changes in the cpu buffer implementation.
Signed-off-by: Robert Richter <robert.richter@amd.com>

This removes the unused cpu function parameter.

Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>

Trivial patch.

Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>

This patch restores default values for:

/dev/oprofile/cpu_buffer_size
/dev/oprofile/buffer_watershed
/dev/oprofile/buffer_size

when creating the oprofilefs:

 # opcontrol --deinit
 # opcontrol --init
 # cat /dev/oprofile/cpu_buffer_size
 8192
 # echo 5123 > /dev/oprofile/cpu_buffer_size
 # cat /dev/oprofile/cpu_buffer_size
 5123
 # opcontrol --deinit
 # opcontrol --init
 # cat /dev/oprofile/cpu_buffer_size
 8192
 # opcontrol --deinit

This sets the values in a defined state. Before, there was no way to
restore the defaults without rebooting the system or reloading the
module.
Signed-off-by: Robert Richter <robert.richter@amd.com>

Signed-off-by: Robert Richter <robert.richter@amd.com>

Implementation of pairwise init/exit funcions for IBS and IBS NMI
setup. There are also some function renames and the removal of forward
function declarations.
Signed-off-by: Robert Richter <robert.richter@amd.com>

This is part of the cpu buffer rework.
Signed-off-by: Robert Richter <robert.richter@amd.com>

Signed-off-by: Robert Richter <robert.richter@amd.com>

Signed-off-by: Robert Richter <robert.richter@amd.com>

The cpu argument is no longer part of the parameter list.
Signed-off-by: Robert Richter <robert.richter@amd.com>