linux-stable/drivers/gpu/drm/i915/i915_pmu.h
Tvrtko Ursulin 4c83f0a788 drm/i915/pmu: Fix sleep under atomic in RC6 readout
We are not allowed to call intel_runtime_pm_get from the PMU counter read
callback since the former can sleep, and the latter is running under IRQ
context.

To workaround this, we record the last known RC6 and while runtime
suspended estimate its increase by querying the runtime PM core
timestamps.

Downside of this approach is that we can temporarily lose a chunk of RC6
time, from the last PMU read-out to runtime suspend entry, but that will
eventually catch up, once device comes back online and in the presence of
PMU queries.

Also, we have to be careful not to overshoot the RC6 estimate, so once
resumed after a period of approximation, we only update the counter once
it catches up. With the observation that RC6 is increasing while the
device is suspended, this should not pose a problem and can only cause
slight inaccuracies due clock base differences.

v2: Simplify by estimating on top of PM core counters. (Imre)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104943
Fixes: 6060b6aec0 ("drm/i915/pmu: Add RC6 residency metrics")
Testcase: igt/perf_pmu/rc6-runtime-pm
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: intel-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180206183311.17924-1-tvrtko.ursulin@linux.intel.com
(cherry picked from commit 1fe699e301)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180213095747.2424-3-tvrtko.ursulin@linux.intel.com
2018-02-13 16:56:03 -08:00

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C

/*
* Copyright © 2017 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
*/
#ifndef __I915_PMU_H__
#define __I915_PMU_H__
enum {
__I915_SAMPLE_FREQ_ACT = 0,
__I915_SAMPLE_FREQ_REQ,
__I915_SAMPLE_RC6,
__I915_SAMPLE_RC6_ESTIMATED,
__I915_NUM_PMU_SAMPLERS
};
/**
* How many different events we track in the global PMU mask.
*
* It is also used to know to needed number of event reference counters.
*/
#define I915_PMU_MASK_BITS \
((1 << I915_PMU_SAMPLE_BITS) + \
(I915_PMU_LAST + 1 - __I915_PMU_OTHER(0)))
struct i915_pmu_sample {
u64 cur;
};
struct i915_pmu {
/**
* @node: List node for CPU hotplug handling.
*/
struct hlist_node node;
/**
* @base: PMU base.
*/
struct pmu base;
/**
* @lock: Lock protecting enable mask and ref count handling.
*/
spinlock_t lock;
/**
* @timer: Timer for internal i915 PMU sampling.
*/
struct hrtimer timer;
/**
* @enable: Bitmask of all currently enabled events.
*
* Bits are derived from uAPI event numbers in a way that low 16 bits
* correspond to engine event _sample_ _type_ (I915_SAMPLE_QUEUED is
* bit 0), and higher bits correspond to other events (for instance
* I915_PMU_ACTUAL_FREQUENCY is bit 16 etc).
*
* In other words, low 16 bits are not per engine but per engine
* sampler type, while the upper bits are directly mapped to other
* event types.
*/
u64 enable;
/**
* @enable_count: Reference counts for the enabled events.
*
* Array indices are mapped in the same way as bits in the @enable field
* and they are used to control sampling on/off when multiple clients
* are using the PMU API.
*/
unsigned int enable_count[I915_PMU_MASK_BITS];
/**
* @timer_enabled: Should the internal sampling timer be running.
*/
bool timer_enabled;
/**
* @sample: Current and previous (raw) counters for sampling events.
*
* These counters are updated from the i915 PMU sampling timer.
*
* Only global counters are held here, while the per-engine ones are in
* struct intel_engine_cs.
*/
struct i915_pmu_sample sample[__I915_NUM_PMU_SAMPLERS];
/**
* @suspended_jiffies_last: Cached suspend time from PM core.
*/
unsigned long suspended_jiffies_last;
};
#ifdef CONFIG_PERF_EVENTS
void i915_pmu_register(struct drm_i915_private *i915);
void i915_pmu_unregister(struct drm_i915_private *i915);
void i915_pmu_gt_parked(struct drm_i915_private *i915);
void i915_pmu_gt_unparked(struct drm_i915_private *i915);
#else
static inline void i915_pmu_register(struct drm_i915_private *i915) {}
static inline void i915_pmu_unregister(struct drm_i915_private *i915) {}
static inline void i915_pmu_gt_parked(struct drm_i915_private *i915) {}
static inline void i915_pmu_gt_unparked(struct drm_i915_private *i915) {}
#endif
#endif