linux-stable.git/arch/arm/kernel/perf_event_cpu.c, branch linux-3.19.y

arm: perf: fold hotplug notifier into arm_pmu

2014-10-30T12:17:01+00:00

Handling multiple PMUs using a single hotplug notifier requires a list
of PMUs to be maintained, with synchronisation in the probe, remove, and
notify paths. This is error-prone and makes the code much harder to
maintain.

Instead of using a single notifier, we can dynamically allocate a
notifier block per-PMU. The end result is the same, but the list of PMUs
is implicit in the hotplug notifier list rather than within a perf-local
data structure, which makes the code far easier to handle.

Signed-off-by: Mark Rutland 
Reviewed-by: Stephen Boyd 
Signed-off-by: Will Deacon

arm: perf: dynamically allocate cpu hardware data

2014-10-30T12:17:00+00:00

To support multiple PMUs, each PMU will need its own accounting data.
As we don't know how (in general) many PMUs we'll have to support at
compile-time, we must allocate the data at runtime dynamically

Signed-off-by: Mark Rutland 
Reviewed-by: Stephen Boyd 
Signed-off-by: Will Deacon

arm: perf: fold percpu_pmu into pmu_hw_events

2014-10-30T12:17:00+00:00

Currently the percpu_pmu pointers used as percpu_irq dev_id values are
defined separately from the other per-cpu accounting data, which make
dynamically allocating the data (as will be required for systems with
heterogeneous CPUs) difficult.

This patch moves the percpu_pmu pointers into pmu_hw_events (which is
itself allocated per cpu), which will allow for easier dynamic
allocation. Both percpu and regular irqs are requested using percpu_pmu
pointers as tokens, freeing us from having to know whether an irq is
percpu within the handler, and thus avoiding a radix tree lookup on the
handler path.

Signed-off-by: Mark Rutland 
Reviewed-by: Will Deacon 
Reviewed-by: Stephen Boyd 
Tested-by: Stephen Boyd 
Signed-off-by: Will Deacon

arm: perf: kill get_hw_events()

2014-10-30T12:17:00+00:00

Now that the arm pmu code is limited to CPU PMUs the get_hw_events()
function is superfluous, as we'll always have a set of per-cpu
pmu_hw_events structures.

This patch removes the get_hw_events() function, replacing it with
a percpu hw_events pointer. Uses of get_hw_events are updated to use
this_cpu_ptr.

Signed-off-by: Mark Rutland 
Reviewed-by: Will Deacon 
Reviewed-by: Stephen Boyd 
Signed-off-by: Will Deacon

arm: perf: limit size of accounting data

2014-10-30T12:16:59+00:00

Commit 3fc2c83087 (ARM: perf: remove event limit from pmu_hw_events) got
rid of the upper limit on the number of events an arm_pmu could handle,
but introduced additional complexity and places a burden on each PMU
driver to allocate accounting data somehow. So far this has not
generally been useful as the only users of arm_pmu are the CPU backend
and the CCI driver.

Now that the CCI driver plugs into the perf subsystem directly, we can
remove some of the complexities that get in the way of supporting
heterogeneous CPU PMUs.

This patch restores the original limits on pmu_hw_events fields such
that the pmu_hw_events data can be allocated as a contiguous block. This
will simplify dynamic pmu_hw_events allocation in later patches.

Signed-off-by: Mark Rutland 
Reviewed-by: Will Deacon 
Reviewed-by: Stephen Boyd 
Tested-by: Stephen Boyd 
Signed-off-by: Will Deacon

arm: perf: use IDR types for CPU PMUs

2014-10-30T12:16:59+00:00

For systems with heterogeneous CPUs (e.g. big.LITTLE systems) the PMUs
can be different in each cluster, and not all events can be migrated
between clusters. To allow userspace to deal with this, it must be
possible to address each PMU independently.

This patch changes PMUs to be registered with dynamic (IDR) types,
allowing them to be targeted individually. Each PMU's type can be found
in ${SYSFS_ROOT}/bus/event_source/devices/${PMU_NAME}/type.

From userspace, raw events can be targeted at a specific PMU:
$ perf stat -e ${PMU_NAME}/config=V,config1=V1,.../

Doing this does not break existing tools which use existing perf types:
when perf core can't find a PMU of matching type (in perf_init_event)
it'll iterate over the set of all PMUs. If a compatible PMU exists,
it'll be found eventually. If more than one compatible PMU exists, the
event will be handled by whichever PMU happens to be earlier in the pmus
list (which currently will be the last compatible PMU registered).

Signed-off-by: Mark Rutland 
Reviewed-by: Will Deacon 
Signed-off-by: Will Deacon

arm: perf: make PMU probing data-driven

2014-10-30T12:16:59+00:00

The current PMU probing logic consists of a single switch statement,
which means that the core arm_pmu core in perf_event_cpu.c needs to know
about every CPU PMU variant supported by a driver using the arm_pmu
framework. This makes it rather difficult to decouple the drivers from
the (otherwise generic) probing code.

The patch refactors that switch statement to a table-driven lookup,
separating the logic and knowledge (in the form of the table). Later
patches will split the table across the relevant PMU drivers, which can
pass their tables to the generic probing function.

Signed-off-by: Mark Rutland 
Reviewed-by: Will Deacon 
Reviewed-by: Stephen Boyd 
Signed-off-by: Will Deacon

arm: perf: add missing pr_info newlines

2014-10-30T12:16:59+00:00

Most of the pr_info format strings in perf_event_cpu.c are missing
newlines. Currently we get away with this as the format strings for
subsequent calls to printk (including all pr_* calls) begin with a log
prefix, and the printk core adds the omitted newline for this case.
While generates the output we expect, we probably should not rely on the
format of successive printk calls in order to get legible output.

This patch adds the missing newlines to pr_info format strings in
perf_event_cpu.c, making them consistent with the format strings for
other pr_info, warn, and pr_err calls, and preventing potentially
illegible output if the next printk/pr_* format string doesn't begin
with a log prefix.

Signed-off-by: Mark Rutland 
Reviewed-by: Stephen Boyd 
Signed-off-by: Will Deacon

ARM: perf: use pr_* instead of printk

2014-10-30T12:16:58+00:00

There are a few remaining uses of printk in the ARM perf code, so move
them over to the pr_* variants instead.

Reported-by: Russell King 
Signed-off-by: Will Deacon

Merge branches 'fiq' (early part), 'fixes', 'l2c' (early part) and 'misc' into for-next

2014-10-02T20:47:02+00:00