This patch introduces struct ibs_state that will extended by additinal
members in follow-on patches.
Signed-off-by: Robert Richter <robert.richter@amd.com>
Since oprofile is setting up ibs_op/dispatched_ops in the fs only if
the feature is available, its corresponding variable
ibs_config.dispatched_ops is only set, if the feature is
available. Thus the check is duplicate and can be removed.
Signed-off-by: Robert Richter <robert.richter@amd.com>
There are IBS CPUID feature flags in CPUID Fn8000_001B to detect if
the cpu supports IBS fetch sampling (FetchSam) and/or IBS execution
sampling (OpSam). This patch adds checks if the both features are
available.
Spec:
http://support.amd.com/us/Processor_TechDocs/31116.pdf
Signed-off-by: Robert Richter <robert.richter@amd.com>
Current IBS code is not hotplug capable. An offline cpu might not be
initialized or deinitialized properly. This patch fixes this by
removing on_each_cpu() functions. The IBS init/deinit code is executed
in the per-cpu functions model->setup_ctrs() and model->cpu_down()
which are also called by hotplug notifiers. model->cpu_down() replaces
model->exit() that became obsolete.
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>
In case a counter is already reserved by the watchdog or perf_event
subsystem, oprofile ignored this counters silently. This case is
handled now and oprofile_setup() now reports an error.
Signed-off-by: Robert Richter <robert.richter@amd.com>
For AMD's and Intel's P6 generic performance counters have pairwise
counter and control msrs. This patch changes the counter reservation
in a way that both msrs must be registered. It joins some counter
loops and also removes the unnecessary NUM_CONTROLS macro in the AMD
implementation.
Signed-off-by: Robert Richter <robert.richter@amd.com>
For consistency reasons this patch renames
ARCH_PERFMON_EVENTSEL0_ENABLE to ARCH_PERFMON_EVENTSEL_ENABLE.
The following is performed:
$ sed -i -e s/ARCH_PERFMON_EVENTSEL0_ENABLE/ARCH_PERFMON_EVENTSEL_ENABLE/g \
arch/x86/include/asm/perf_event.h arch/x86/kernel/cpu/perf_event.c \
arch/x86/kernel/cpu/perf_event_p6.c \
arch/x86/kernel/cpu/perfctr-watchdog.c \
arch/x86/oprofile/op_model_amd.c arch/x86/oprofile/op_model_ppro.c
Signed-off-by: Robert Richter <robert.richter@amd.com>
This patch moves code from oprofile to perf_event.h to make it also
available for usage by perf.
Signed-off-by: Robert Richter <robert.richter@amd.com>
During switching virtual counters there is access to perfctr msrs. If
the counter is not available this fails due to an invalid
address. This patch fixes this.
Cc: stable@kernel.org
Signed-off-by: Robert Richter <robert.richter@amd.com>
Multiple virtual counters share one physical counter. The reservation
of virtual counters fails due to duplicate allocation of the same
counter. The counters are already reserved. Thus, virtual counter
reservation may removed at all. This also makes the code easier.
Cc: stable@kernel.org
Signed-off-by: Robert Richter <robert.richter@amd.com>
This patch generates a warning if a counter is already active.
Implemented for AMD and P6 models. P4 is not supported.
Cc: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Cc: Shashi Belur <shashi-kiran.belur@hp.com>
Cc: Tony Jones <tonyj@suse.de>
Signed-off-by: Robert Richter <robert.richter@amd.com>
IBS selects an op (execution operation) for sampling by counting
either cycles or dispatched ops. Better statistical samples can be
produced by adding a software generated random offset to the periodic
op counter value with each sample.
This patch adds software randomization to the IBS periodic op
counter. The lower 12 bits of the 20 bit counter are
randomized. IbsOpCurCnt is initialized with a 12 bit random value.
There is a work around if the hw can not write to IbsOpCurCnt. Then
the lower 8 bits of the 16 bit IbsOpMaxCnt [15:0] value are randomized
in the range of -128 to +127 by adding/subtracting an offset to the
maximum count (IbsOpMaxCnt).
The linear feedback shift register (LFSR) algorithm is used for
pseudo-random number generation to have low impact to the memory
system.
Signed-off-by: Robert Richter <robert.richter@amd.com>
This patch implements a linear feedback shift register (LFSR) for
pseudo-random number generation for IBS.
For IBS measurements it would be good to minimize memory traffic in
the interrupt handler since every access pollutes the data
caches. Computing a maximal period LFSR just needs shifts and ORs.
The LFSR method is good enough to randomize the ops at low
overhead. 16 pseudo-random bits are enough for the implementation and
it doesn't matter that the pattern repeats with a fairly short
cycle. It only needs to break up (hard) periodic sampling behavior.
The logic was designed by Paul Drongowski.
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
This patch adds IBS feature detection using cpuid flags. An IBS
capability mask is introduced to test for certain IBS features. The
bit mask is the same as for IBS cpuid feature flags (Fn8000_001B_EAX),
but bit 0 is used to indicate the existence of IBS.
The patch also changes the handling of the IbsOpCntCtl bit (periodic
op counter count control). The oprofilefs file for this feature
(ibs_op/dispatched_ops) will be only exposed if the feature is
available, also the default for the bit is set to count clock cycles.
In general, the userland can detect the availability of a feature by
checking for the corresponding file in oprofilefs. If it exists, the
feature also exists. This may lead to a dynamic file layout depending
on the cpu type with that the userland has to deal with. Current
opcontrol is compatible.
Signed-off-by: Robert Richter <robert.richter@amd.com>
Standard AMD systems have the same number of nodes as there are
northbridge devices. However, there may kernel configurations
(especially for 32 bit) or system setups exist, where the node number
is different or it can not be detected properly. Thus the check is not
reliable and may fail though IBS setup was fine. For this reason it is
better to remove the check.
Cc: stable <stable@kernel.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>
OProfile support for IBS is now for several versions in the
kernel. The feature is stable now and the code can be activated
permanently.
As a side effect IBS now works also on nosmp configs.
Signed-off-by: Robert Richter <robert.richter@amd.com>
arch/x86/oprofile/op_model_amd.c: In function 'op_amd_handle_ibs':
arch/x86/oprofile/op_model_amd.c:217: warning: no return statement in function returning non-void
Fix this by making op_amd_handle_ibs() return void.
Cc: Robert Richter <robert.richter@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>
This reverts commit 21e7087821.
Instead Andrew's patch will be applied he posted at the same time.
Signed-off-by: Robert Richter <robert.richter@amd.com>
This patch removes the const qualifier from struct
op_x86_model_spec to make model parameters changable.
Signed-off-by: Robert Richter <robert.richter@amd.com>
This patch moves some multiplexing code to the new function
op_mux_fill_in_addresses(). Also, the whole multiplexing code is now
at a single location.
Signed-off-by: Robert Richter <robert.richter@amd.com>
Use the corresponding macros when iterating over counter and control
registers. Since NUM_CONTROLS and NUM_COUNTERS are equal for AMD cpus
the fix is more a cosmetical change.
Signed-off-by: Robert Richter <robert.richter@amd.com>
The number of hardware counters is limited. The multiplexing feature
enables OProfile to gather more events than counters are provided by
the hardware. This is realized by switching between events at an user
specified time interval.
A new file (/dev/oprofile/time_slice) is added for the user to specify
the timer interval in ms. If the number of events to profile is higher
than the number of hardware counters available, the patch will
schedule a work queue that switches the event counter and re-writes
the different sets of values into it. The switching mechanism needs to
be implemented for each architecture to support multiplexing. This
patch only implements AMD CPU support, but multiplexing can be easily
extended for other models and architectures.
There are follow-on patches that rework parts of this patch.
Signed-off-by: Jason Yeh <jason.yeh@amd.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
When casting the counter value to a 64 bit value in 32 bit mode, sign
extension may lead to broken counter values. This patch fixes this by
casting to (u64) instead of (s64).
Signed-off-by: Robert Richter <robert.richter@amd.com>
op_amd_handle_ibs() should return 0 when IBS is not present or not defined.
Fix compilation warning:
CC [M] arch/x86/oprofile/op_model_amd.o
arch/x86/oprofile/op_model_amd.c: In function ‘op_amd_handle_ibs’:
arch/x86/oprofile/op_model_amd.c:217: warning: no return statement in function returning non-void
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
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 <robert.richter@amd.com>
The IBS code internally uses 32 bit values (a low and a high value) to
represent a 64 bit value. This patch changes this and now 64 bit
values are used instead. 64 bit MSR functions can be used now.
No functional changes.
Signed-off-by: Robert Richter <robert.richter@amd.com>
The patch replaces all CTRL_SET_*ACTIVE macros. 64 bit MSR functions
and 64 bit counter values are used now. The code uses bit masks from
<asm/intel_arch_perfmon.h>.
Signed-off-by: Robert Richter <robert.richter@amd.com>
The patch replaces all CTR_OVERFLOWED macros. 64 bit MSR functions and
64 bit counter values are used now. Thus, it will be easier to later
extend the models to use more than 32 bit width counters.
Signed-off-by: Robert Richter <robert.richter@amd.com>
This patch introduces op_x86_get_ctrl() to calculate the value of the
performance control register. This is generic code usable for all
models. The event and reserved masks are model specific and stored in
struct op_x86_model_spec. 64 bit MSR functions are used now. The patch
removes many hard to read macros used for ctrl calculation.
The function op_x86_get_ctrl() is common code and the first step to
further merge performance counter implementations for x86 models.
Signed-off-by: Robert Richter <robert.richter@amd.com>
In follow-on patches the setup_ctrs() functions will need data that
describes the model. This patch extends the function argument list to
pass a pointer of the model to these function.
Signed-off-by: Robert Richter <robert.richter@amd.com>
The use of the macros has no effect. The oprofilefs has to be extended
first to support these features.
Signed-off-by: Robert Richter <robert.richter@amd.com>
The macros CTRL_READ() and CTRL_WRITE() make the code hard to read and
maintain. This patch replaces them by rdmsr()/wrmsr() functions and
simplifies the code.
Signed-off-by: Robert Richter <robert.richter@amd.com>
There are duplicate macro implementations in model specific code. This
patch moves all common macros to op_x86_model.h.
Signed-off-by: Robert Richter <robert.richter@amd.com>
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 <robert.richter@amd.com>
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 <robert.richter@amd.com>
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>
