15 Feb, 2011
1 commit
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This patch introduces a new oprofile sample add function
(oprofile_add_ext_hw_sample) that can also take task_struct as an
argument, which is used by the hwsampler kernel module when copying
hardware samples to OProfile buffers.Applied with following changes:
* removed #include
* whitespace changes
* removed conditional compilation (CONFIG_HAVE_HWSAMPLER)
* modified order of functions
* fix missing function definition in header fileSigned-off-by: Mahesh Salgaonkar
Signed-off-by: Maran Pakkirisamy
Signed-off-by: Heinz Graalfs
Acked-by: Heiko Carstens
Signed-off-by: Robert Richter
29 Oct, 2010
1 commit
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flush_scheduled_work() is deprecated and scheduled to be removed.
sync_stop() currently cancels cpu_buffer works inside buffer_mutex and
flushes the system workqueue outside. Instead, split end_cpu_work()
into two parts - stopping further work enqueues and flushing works -
and do the former inside buffer_mutex and latter outside.For stable kernels v2.6.35.y and v2.6.36.y.
Signed-off-by: Tejun Heo
Cc: stable@kernel.org
Signed-off-by: Robert Richter
25 Aug, 2010
1 commit
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This patch fixes a crash during shutdown reported below. The crash is
caused by accessing already freed task structs. The fix changes the
order for registering and unregistering notifier callbacks.All notifiers must be initialized before buffers start working. To
stop buffer synchronization we cancel all workqueues, unregister the
notifier callback and then flush all buffers. After all of this we
finally can free all tasks listed.This should avoid accessing freed tasks.
On 22.07.10 01:14:40, Benjamin Herrenschmidt wrote:
> So the initial observation is a spinlock bad magic followed by a crash
> in the spinlock debug code:
>
> [ 1541.586531] BUG: spinlock bad magic on CPU#5, events/5/136
> [ 1541.597564] Unable to handle kernel paging request for data at address 0x6b6b6b6b6b6b6d03
>
> Backtrace looks like:
>
> spin_bug+0x74/0xd4
> ._raw_spin_lock+0x48/0x184
> ._spin_lock+0x10/0x24
> .get_task_mm+0x28/0x8c
> .sync_buffer+0x1b4/0x598
> .wq_sync_buffer+0xa0/0xdc
> .worker_thread+0x1d8/0x2a8
> .kthread+0xa8/0xb4
> .kernel_thread+0x54/0x70
>
> So we are accessing a freed task struct in the work queue when
> processing the samples.Reported-by: Benjamin Herrenschmidt
Cc: stable@kernel.org
Signed-off-by: Robert Richter
04 May, 2010
1 commit
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http://lkml.org/lkml/2010/4/27/285
Protect against dereferencing regs when it's NULL, and
force a magic number into pc to prevent too deep processing.
This approach permits the dropped samples to be tallied as
invalid Instruction Pointer events.e.g. output from about 15mins at 10kHz sample rate:
Nr. samples received: 2565380
Nr. samples lost invalid pc: 4Signed-off-by: Phil Carmody
Signed-off-by: Robert Richter
23 Apr, 2010
2 commits
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Conflicts:
drivers/oprofile/cpu_buffer.cSigned-off-by: Robert Richter
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oprofile used a double buffer scheme for its cpu event buffer
to avoid races on reading with the old locked ring buffer.But that is obsolete now with the new ring buffer, so simply
use a single buffer. This greatly simplifies the code and avoids
a lot of sample drops on large runs, especially with call graph.Based on suggestions from Steven Rostedt
For stable kernels from v2.6.32, but not earlier.
Signed-off-by: Andi Kleen
Cc: Steven Rostedt
Cc: stable
Signed-off-by: Robert Richter
01 Apr, 2010
1 commit
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Currently, when the ring buffer drops events, it does not record
the fact that it did so. It does inform the writer that the event
was dropped by returning a NULL event, but it does not put in any
place holder where the event was dropped.This is not a trivial thing to add because the ring buffer mostly
runs in overwrite (flight recorder) mode. That is, when the ring
buffer is full, new data will overwrite old data.In a produce/consumer mode, where new data is simply dropped when
the ring buffer is full, it is trivial to add the placeholder
for dropped events. When there's more room to write new data, then
a special event can be added to notify the reader about the dropped
events.But in overwrite mode, any new write can overwrite events. A place
holder can not be inserted into the ring buffer since there never
may be room. A reader could also come in at anytime and miss the
placeholder.Luckily, the way the ring buffer works, the read side can find out
if events were lost or not, and how many events. Everytime a write
takes place, if it overwrites the header page (the next read) it
updates a "overrun" variable that keeps track of the number of
lost events. When a reader swaps out a page from the ring buffer,
it can record this number, perfom the swap, and then check to
see if the number changed, and take the diff if it has, which would be
the number of events dropped. This can be stored by the reader
and returned to callers of the reader.Since the reader page swap will fail if the writer moved the head
page since the time the reader page set up the swap, this gives room
to record the overruns without worrying about races. If the reader
sets up the pages, records the overrun, than performs the swap,
if the swap succeeds, then the overrun variable has not been
updated since the setup before the swap.For binary readers of the ring buffer, a flag is set in the header
of each sub page (sub buffer) of the ring buffer. This flag is embedded
in the size field of the data on the sub buffer, in the 31st bit (the size
can be 32 or 64 bits depending on the architecture), but only 27
bits needs to be used for the actual size (less actually).We could add a new field in the sub buffer header to also record the
number of events dropped since the last read, but this will change the
format of the binary ring buffer a bit too much. Perhaps this change can
be made if the information on the number of events dropped is considered
important enough.Note, the notification of dropped events is only used by consuming reads
or peeking at the ring buffer. Iterating over the ring buffer does not
keep this information because the necessary data is only available when
a page swap is made, and the iterator does not swap out pages.Cc: Robert Richter
Cc: Andi Kleen
Cc: Li Zefan
Cc: Arnaldo Carvalho de Melo
Cc: "Luis Claudio R. Goncalves"
Cc: Frederic Weisbecker
Signed-off-by: Steven Rostedt
29 Oct, 2009
1 commit
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This patch updates percpu related symbols in oprofile such that percpu
symbols are unique and don't clash with local symbols. This serves
two purposes of decreasing the possibility of global percpu symbol
collision and allowing dropping per_cpu__ prefix from percpu symbols.* drivers/oprofile/cpu_buffer.c: s/cpu_buffer/op_cpu_buffer/
Partly based on Rusty Russell's "alloc_percpu: rename percpu vars
which cause name clashes" patch.Signed-off-by: Tejun Heo
Acked-by: Robert Richter
Cc: Rusty Russell
12 Jun, 2009
1 commit
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The IBS implemention writes 64 bit register values to the cpu buffer
by writing two 32 values using oprofile_add_data(). This patch
introduces oprofile_add_data64() to write a single 64 bit value to the
buffer.Signed-off-by: Robert Richter
11 Jun, 2009
1 commit
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This became obsolete with this commit:
6dad828 oprofile: port to the new ring_buffer
Signed-off-by: Robert Richter
07 May, 2009
1 commit
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The unit of oprofile_cpu_buffer_size is in samples, but was allocated
in bytes. This led to the allocation of too small cpu buffers. This
patch recalculates the buffer size in bytes taking also the
ring_buffer_event header size into account.Reported-by: Suravee Suthikulpanit
Signed-off-by: Robert Richter
06 Feb, 2009
1 commit
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Oprofile's ring-buffer use was not considered.
Signed-off-by: Ingo Molnar
18 Jan, 2009
1 commit
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Impact: fix crash
In case of losing samples struct op_entry could have been used
uninitialized causing e.g. a wrong preemption count or NULL pointer
access. This patch fixes this.Signed-off-by: Robert Richter
Signed-off-by: Ingo Molnar
08 Jan, 2009
11 commits
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This patch creates the new functions
oprofile_write_reserve()
oprofile_add_data()
oprofile_write_commit()and makes them part of the oprofile api.
Signed-off-by: Robert Richter
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The ifdefs can be removed since the code is no longer ibs specific and
can be used for other purposes as well. IBS specific code is only in
op_model_amd.c.Signed-off-by: Robert Richter
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The new ring buffer implementation allows the storage of samples with
different size. This patch implements the usage of the new sample
format to store ibs samples in the cpu buffer. Until now, writing to
the cpu buffer could lead to incomplete sampling sequences since IBS
samples were transfered in multiple samples. Due to a full buffer,
data could be lost at any time. This can't happen any more since the
complete data is reserved in advance and then stored in a single
sample.Signed-off-by: Robert Richter
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This function can be used to attach data to a sample. It returns the
remaining free buffer size that has been reserved with
op_cpu_buffer_write_reserve().Signed-off-by: Robert Richter
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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
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This implements the support of samples with attached data.
Signed-off-by: Robert Richter
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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
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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
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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
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Signed-off-by: Robert Richter
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Signed-off-by: Robert Richter
30 Dec, 2008
4 commits
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Signed-off-by: Robert Richter
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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
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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
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Reordering code to keep alloc/free functions together.
Signed-off-by: Robert Richter
29 Dec, 2008
2 commits
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This patch moves ring buffer inline functions to cpu_buffer.c.
Cc: Andrew Morton
Signed-off-by: Robert Richter -
This patch renames cpu buffer functions to something more oprofile
specific names. Functions will be moved to the global name space.Cc: Andrew Morton
Signed-off-by: Robert Richter
17 Dec, 2008
1 commit
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This patch renames kernel-wide identifiers to something more oprofile
specific names.Cc: Andrew Morton
Signed-off-by: Robert Richter
11 Dec, 2008
2 commits
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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
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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
10 Dec, 2008
6 commits
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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
Signed-off-by: Robert Richter -
This is in preparation for changes in the cpu buffer implementation.
Signed-off-by: Robert Richter
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This is in preparation for changes in the cpu buffer implementation.
Signed-off-by: Robert Richter
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This is in preparation for changes in the cpu buffer implementation.
Signed-off-by: Robert Richter
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Signed-off-by: Robert Richter
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This fixes the coding style of some comments.
Signed-off-by: Robert Richter
24 Oct, 2008
1 commit
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* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rric/oprofile: (21 commits)
OProfile: Fix buffer synchronization for IBS
oprofile: hotplug cpu fix
oprofile: fixing whitespaces in arch/x86/oprofile/*
oprofile: fixing whitespaces in arch/x86/oprofile/*
oprofile: fixing whitespaces in drivers/oprofile/*
x86/oprofile: add the logic for enabling additional IBS bits
x86/oprofile: reordering functions in nmi_int.c
x86/oprofile: removing unused function parameter in add_ibs_begin()
oprofile: more whitespace fixes
oprofile: whitespace fixes
OProfile: Rename IBS sysfs dir into "ibs_op"
OProfile: Rework string handling in setup_ibs_files()
OProfile: Rework oprofile_add_ibs_sample() function
oprofile: discover counters for op ppro too
oprofile: Implement Intel architectural perfmon support
oprofile: Don't report Nehalem as core_2
oprofile: drop const in num counters field
Revert "Oprofile Multiplexing Patch"
x86, oprofile: BUG: using smp_processor_id() in preemptible code
x86/oprofile: fix on_each_cpu build error
...Manually fixed trivial conflicts in
drivers/oprofile/{cpu_buffer.c,event_buffer.h}
