This changes the powerpc perf_counter back-end to use unsigned long
types for hardware register values and for the value/mask pairs used
in checking whether a given set of events fit within the hardware
constraints. This is in preparation for adding support for the PMU
on some 32-bit powerpc processors. On 32-bit processors the hardware
registers are only 32 bits wide, and the PMU structure is generally
simpler, so 32 bits should be ample for expressing the hardware
constraints. On 64-bit processors, unsigned long is 64 bits wide,
so using unsigned long vs. u64 (unsigned long long) makes no actual
difference.
This makes some other very minor changes: adjusting whitespace to line
things up in initialized structures, and simplifying some code in
hw_perf_disable().
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linuxppc-dev@ozlabs.org
Cc: benh@kernel.crashing.org
LKML-Reference: <19000.55473.26174.331511@cargo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This enables the perf_counter subsystem on 32-bit powerpc. Since we
don't have any support for hardware counters on 32-bit powerpc yet,
only software counters can be used.
Besides selecting HAVE_PERF_COUNTERS for 32-bit powerpc as well as
64-bit, the main thing this does is add an implementation of
set_perf_counter_pending(). This needs to arrange for
perf_counter_do_pending() to be called when interrupts are enabled.
Rather than add code to local_irq_restore as 64-bit does, the 32-bit
set_perf_counter_pending() generates an interrupt by setting the
decrementer to 1 so that a decrementer interrupt will become pending
in 1 or 2 timebase ticks (if a decrementer interrupt isn't already
pending). When interrupts are enabled, timer_interrupt() will be
called, and some new code in there calls perf_counter_do_pending().
We use a per-cpu array of flags to indicate whether we need to call
perf_counter_do_pending() or not.
This introduces a couple of new Kconfig symbols: PPC_HAVE_PMU_SUPPORT,
which is selected by processor families for which we have hardware PMU
support (currently only PPC64), and PPC_PERF_CTRS, which enables the
powerpc-specific perf_counter back-end.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linuxppc-dev@ozlabs.org
Cc: benh@kernel.crashing.org
LKML-Reference: <19000.55404.103840.393470@cargo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
At present, every architecture that supports perf_counters has to
declare set_perf_counter_pending() in its arch-specific headers.
This consolidates the declarations into a single declaration in one
common place, include/linux/perf_counter.h. On powerpc, we continue
to provide a static inline definition of set_perf_counter_pending()
in the powerpc hw_irq.h.
Also, this removes from the x86 perf_counter.h the unused null
definitions of {test,clear}_perf_counter_pending.
Reported-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: benh@kernel.crashing.org
LKML-Reference: <18998.13388.920691.523227@cargo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This adds tables of event codes for the generalized cache events for
all the currently supported powerpc processors: POWER{4,5,5+,6,7} and
PPC970*, plus powerpc-specific code to use these tables when a
generalized cache event is requested.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <18992.36430.933526.742969@drongo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This uses values from the MMCRA, SIAR and SDAR registers on
powerpc to supply more precise information for overflow events,
including a data address when PERF_RECORD_ADDR is specified.
Since POWER6 uses different bit positions in MMCRA from earlier
processors, this converts the struct power_pmu limited_pmc5_6
field, which only had 0/1 values, into a flags field and
defines bit values for its previous use (PPMU_LIMITED_PMC5_6)
and a new flag (PPMU_ALT_SIPR) to indicate that the processor
uses the POWER6 bit positions rather than the earlier
positions. It also adds definitions in reg.h for the new and
old positions of the bit that indicates that the SIAR and SDAR
values come from the same instruction.
For the data address, the SDAR value is supplied if we are not
doing instruction sampling. In that case there is no guarantee
that the address given in the PERF_RECORD_ADDR subrecord will
correspond to the instruction whose address is given in the
PERF_RECORD_IP subrecord.
If instruction sampling is enabled (e.g. because this counter
is counting a marked instruction event), then we only supply
the SDAR value for the PERF_RECORD_ADDR subrecord if it
corresponds to the instruction whose address is in the
PERF_RECORD_IP subrecord. Otherwise we supply 0.
[ Impact: support more PMU hardware features on PowerPC ]
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <18955.37028.48861.555309@drongo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Although the perf_counter API allows 63-bit raw event codes,
internally in the powerpc back-end we had been using 32-bit
event codes. This expands them to 64 bits so that we can add
bits for specifying threshold start/stop events and instruction
sampling modes later.
This also corrects the return value of can_go_on_limited_pmc;
we were returning an event code rather than just a 0/1 value in
some circumstances. That didn't particularly matter while event
codes were 32-bit, but now that event codes are 64-bit it
might, so this fixes it.
[ Impact: extend PowerPC perfcounter interfaces from u32 to u64 ]
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <18955.36874.472452.353104@drongo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
POWER5+ and POWER6 have two hardware counters with limited functionality:
PMC5 counts instructions completed in run state and PMC6 counts cycles
in run state. (Run state is the state when a hardware RUN bit is 1;
the idle task clears RUN while waiting for work to do and sets it when
there is work to do.)
These counters can't be written to by the kernel, can't generate
interrupts, and don't obey the freeze conditions. That means we can
only use them for per-task counters (where we know we'll always be in
run state; we can't put a per-task counter on an idle task), and only
if we don't want interrupts and we do want to count in all processor
modes.
Obviously some counters can't go on a limited hardware counter, but there
are also situations where we can only put a counter on a limited hardware
counter - if there are already counters on that exclude some processor
modes and we want to put on a per-task cycle or instruction counter that
doesn't exclude any processor mode, it could go on if it can use a
limited hardware counter.
To keep track of these constraints, this adds a flags argument to the
processor-specific get_alternatives() functions, with three bits defined:
one to say that we can accept alternative event codes that go on limited
counters, one to say we only want alternatives on limited counters, and
one to say that this is a per-task counter and therefore events that are
gated by run state are equivalent to those that aren't (e.g. a "cycles"
event is equivalent to a "cycles in run state" event). These flags
are computed for each counter and stored in the counter->hw.counter_base
field (slightly wonky name for what it does, but it was an existing
unused field).
Since the limited counters don't freeze when we freeze the other counters,
we need some special handling to avoid getting skew between things counted
on the limited counters and those counted on normal counters. To minimize
this skew, if we are using any limited counters, we read PMC5 and PMC6
immediately after setting and clearing the freeze bit. This is done in
a single asm in the new write_mmcr0() function.
The code here is specific to PMC5 and PMC6 being the limited hardware
counters. Being more general (e.g. having a bitmap of limited hardware
counter numbers) would have meant more complex code to read the limited
counters when freezing and unfreezing the normal counters, with
conditional branches, which would have increased the skew. Since it
isn't necessary for the code to be more general at this stage, it isn't.
This also extends the back-ends for POWER5+ and POWER6 to be able to
handle up to 6 counters rather than the 4 they previously handled.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
LKML-Reference: <18936.19035.163066.892208@cargo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This provides the architecture-specific functions needed to access
PMU hardware on the 64-bit PowerPC processors. It has been designed
for the IBM POWER family (POWER 4/4+/5/5+/6 and PPC970) but will
hopefully also suit other 64-bit PowerPC machines (although probably
not Cell given how different it is in this area). This doesn't
include back-ends for any specific processors.
This implements a system which allows back-ends to express the
constraints that their hardware has on what events can be counted
simultaneously. The constraints are expressed as a 64-bit mask +
64-bit value for each event, and the encoding is capable of
expressing the constraints arising from having a set of multiplexers
feeding an event bus, with some events being available through
multiple multiplexer settings, such as we get on POWER4 and PPC970.
Furthermore, the back-end can supply alternative event codes for
each event, and the constraint checking code will try all possible
combinations of alternative event codes to try to find a combination
that will fit.
Signed-off-by: Paul Mackerras <paulus@samba.org>
