[Intel-gfx] [RFC 04/11] drm/i915/pmu: Expose a PMU interface for perf queries
Rogozhkin, Dmitry V
dmitry.v.rogozhkin at intel.com
Tue Sep 12 02:06:23 UTC 2017
On Mon, 2017-09-11 at 16:25 +0100, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>
> From: Chris Wilson <chris at chris-wilson.co.uk>
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> From: Dmitry Rogozhkin <dmitry.v.rogozhkin at intel.com>
>
> The first goal is to be able to measure GPU (and invidual ring) busyness
> without having to poll registers from userspace. (Which not only incurs
> holding the forcewake lock indefinitely, perturbing the system, but also
> runs the risk of hanging the machine.) As an alternative we can use the
> perf event counter interface to sample the ring registers periodically
> and send those results to userspace.
>
> To be able to do so, we need to export the two symbols from
> kernel/events/core.c to register and unregister a PMU device.
>
> v1-v2 (Chris Wilson):
>
> v2: Use a common timer for the ring sampling.
>
> v3: (Tvrtko Ursulin)
> * Decouple uAPI from i915 engine ids.
> * Complete uAPI defines.
> * Refactor some code to helpers for clarity.
> * Skip sampling disabled engines.
> * Expose counters in sysfs.
> * Pass in fake regs to avoid null ptr deref in perf core.
> * Convert to class/instance uAPI.
> * Use shared driver code for rc6 residency, power and frequency.
>
> v4: (Dmitry Rogozhkin)
> * Register PMU with .task_ctx_nr=perf_invalid_context
> * Expose cpumask for the PMU with the single CPU in the mask
> * Properly support pmu->stop(): it should call pmu->read()
> * Properly support pmu->del(): it should call stop(event, PERF_EF_UPDATE)
> * Make pmu.busy_stats a refcounter to avoid busy stats going away
> with some deleted event.
busy_stats appear later in the patch series. And in your final version
busy_stats remain bool while we rely on events refcounting. So, this
item is misleading. Could you, please, change it giving a credit to
general ref-counting of events which you have rewrote for v5 of this
patch?
> * Expose cpumask for i915 PMU to avoid multiple events creation of
> the same type followed by counter aggregation by perf-stat.
> * Track CPUs getting online/offline to migrate perf context. If (likely)
> cpumask will initially set CPU0, CONFIG_BOOTPARAM_HOTPLUG_CPU0 will be
> needed to see effect of CPU status tracking.
> * End result is that only global events are supported and perf stat
> works correctly.
> * Deny perf driver level sampling - it is prohibited for uncore PMU.
>
> v5: (Tvrtko Ursulin)
>
> * Don't hardcode number of engine samplers.
> * Rewrite event ref-counting for correctness and simplicity.
> * Store initial counter value when starting already enabled events
> to correctly report values to all listeners.
> * Fix RC6 residency readout.
> * Comments, GPL header.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Signed-off-by: Dmitry Rogozhkin <dmitry.v.rogozhkin at intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin at intel.com>
> Cc: Peter Zijlstra <peterz at infradead.org>
> ---
> drivers/gpu/drm/i915/Makefile | 1 +
> drivers/gpu/drm/i915/i915_drv.c | 2 +
> drivers/gpu/drm/i915/i915_drv.h | 76 ++++
> drivers/gpu/drm/i915/i915_pmu.c | 686 ++++++++++++++++++++++++++++++++
> drivers/gpu/drm/i915/i915_reg.h | 3 +
> drivers/gpu/drm/i915/intel_engine_cs.c | 10 +
> drivers/gpu/drm/i915/intel_ringbuffer.c | 25 ++
> drivers/gpu/drm/i915/intel_ringbuffer.h | 25 ++
> include/uapi/drm/i915_drm.h | 58 +++
> 9 files changed, 886 insertions(+)
> create mode 100644 drivers/gpu/drm/i915/i915_pmu.c
>
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 1cb8059a3a16..7b3a0eca62b6 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -26,6 +26,7 @@ i915-y := i915_drv.o \
>
> i915-$(CONFIG_COMPAT) += i915_ioc32.o
> i915-$(CONFIG_DEBUG_FS) += i915_debugfs.o intel_pipe_crc.o
> +i915-$(CONFIG_PERF_EVENTS) += i915_pmu.o
>
> # GEM code
> i915-y += i915_cmd_parser.o \
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 5c111ea96e80..b1f96eb1be16 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1196,6 +1196,7 @@ static void i915_driver_register(struct drm_i915_private *dev_priv)
> struct drm_device *dev = &dev_priv->drm;
>
> i915_gem_shrinker_init(dev_priv);
> + i915_pmu_register(dev_priv);
>
> /*
> * Notify a valid surface after modesetting,
> @@ -1250,6 +1251,7 @@ static void i915_driver_unregister(struct drm_i915_private *dev_priv)
> intel_opregion_unregister(dev_priv);
>
> i915_perf_unregister(dev_priv);
> + i915_pmu_unregister(dev_priv);
>
> i915_teardown_sysfs(dev_priv);
> i915_guc_log_unregister(dev_priv);
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 48daf9552163..62646b8dfb7a 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -40,6 +40,7 @@
> #include <linux/hash.h>
> #include <linux/intel-iommu.h>
> #include <linux/kref.h>
> +#include <linux/perf_event.h>
> #include <linux/pm_qos.h>
> #include <linux/reservation.h>
> #include <linux/shmem_fs.h>
> @@ -2190,6 +2191,69 @@ struct intel_cdclk_state {
> unsigned int cdclk, vco, ref;
> };
>
> +enum {
> + __I915_SAMPLE_FREQ_ACT = 0,
> + __I915_SAMPLE_FREQ_REQ,
> + __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 {
> + /**
> + * @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];
> + /**
> + * @sample: Current counter value for i915 events which need sampling.
> + *
> + * 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.
> + */
> + u64 sample[__I915_NUM_PMU_SAMPLERS];
> +};
> +
> struct drm_i915_private {
> struct drm_device drm;
>
> @@ -2238,6 +2302,7 @@ struct drm_i915_private {
> struct pci_dev *bridge_dev;
> struct i915_gem_context *kernel_context;
> struct intel_engine_cs *engine[I915_NUM_ENGINES];
> + struct intel_engine_cs *engine_class[MAX_ENGINE_CLASS + 1][MAX_ENGINE_INSTANCE + 1];
> struct i915_vma *semaphore;
>
> struct drm_dma_handle *status_page_dmah;
> @@ -2698,6 +2763,8 @@ struct drm_i915_private {
> int irq;
> } lpe_audio;
>
> + struct i915_pmu pmu;
> +
> /*
> * NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
> * will be rejected. Instead look for a better place.
> @@ -3918,6 +3985,15 @@ extern void i915_perf_fini(struct drm_i915_private *dev_priv);
> extern void i915_perf_register(struct drm_i915_private *dev_priv);
> extern void i915_perf_unregister(struct drm_i915_private *dev_priv);
>
> +/* i915_pmu.c */
> +#ifdef CONFIG_PERF_EVENTS
> +extern void i915_pmu_register(struct drm_i915_private *i915);
> +extern void i915_pmu_unregister(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) {}
> +#endif
> +
> /* i915_suspend.c */
> extern int i915_save_state(struct drm_i915_private *dev_priv);
> extern int i915_restore_state(struct drm_i915_private *dev_priv);
> diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
> new file mode 100644
> index 000000000000..2ec892e57143
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/i915_pmu.c
> @@ -0,0 +1,686 @@
> +/*
> + * 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.
> + *
> + */
> +
> +#include <linux/perf_event.h>
> +#include <linux/pm_runtime.h>
> +
> +#include "i915_drv.h"
> +#include "intel_ringbuffer.h"
> +
> +/* Frequency for the sampling timer for events which need it. */
> +#define FREQUENCY 200
> +#define PERIOD max_t(u64, 10000, NSEC_PER_SEC / FREQUENCY)
> +
> +#define ENGINE_SAMPLE_MASK \
> + (BIT(I915_SAMPLE_QUEUED) | \
> + BIT(I915_SAMPLE_BUSY) | \
> + BIT(I915_SAMPLE_WAIT) | \
> + BIT(I915_SAMPLE_SEMA))
> +
> +#define ENGINE_SAMPLE_BITS (1 << I915_PMU_SAMPLE_BITS)
> +
> +static cpumask_t i915_pmu_cpumask = CPU_MASK_NONE;
> +
> +static u8 engine_config_sample(u64 config)
> +{
> + return config & I915_PMU_SAMPLE_MASK;
> +}
> +
> +static u8 engine_event_sample(struct perf_event *event)
> +{
> + return engine_config_sample(event->attr.config);
> +}
> +
> +static u8 engine_event_class(struct perf_event *event)
> +{
> + return (event->attr.config >> I915_PMU_CLASS_SHIFT) & 0xff;
> +}
> +
> +static u8 engine_event_instance(struct perf_event *event)
> +{
> + return (event->attr.config >> I915_PMU_SAMPLE_BITS) & 0xff;
> +}
> +
> +static bool is_engine_config(u64 config)
> +{
> + return config < __I915_PMU_OTHER(0);
> +}
> +
> +static unsigned int config_enabled_bit(u64 config)
> +{
> + if (is_engine_config(config))
> + return engine_config_sample(config);
> + else
> + return ENGINE_SAMPLE_BITS + (config - __I915_PMU_OTHER(0));
> +}
> +
> +static u64 config_enabled_mask(u64 config)
> +{
> + return BIT_ULL(config_enabled_bit(config));
> +}
> +
> +static bool is_engine_event(struct perf_event *event)
> +{
> + return is_engine_config(event->attr.config);
> +}
> +
> +static unsigned int event_enabled_bit(struct perf_event *event)
> +{
> + return config_enabled_bit(event->attr.config);
> +}
> +
> +static bool grab_forcewake(struct drm_i915_private *i915, bool fw)
> +{
> + if (!fw)
> + intel_uncore_forcewake_get(i915, FORCEWAKE_ALL);
> +
> + return true;
> +}
> +
> +static void engines_sample(struct drm_i915_private *dev_priv)
> +{
> + struct intel_engine_cs *engine;
> + enum intel_engine_id id;
> + bool fw = false;
> +
> + if ((dev_priv->pmu.enable & ENGINE_SAMPLE_MASK) == 0)
> + return;
> +
> + if (!dev_priv->gt.awake)
> + return;
> +
> + if (!intel_runtime_pm_get_if_in_use(dev_priv))
> + return;
> +
> + for_each_engine(engine, dev_priv, id) {
> + u32 enable = engine->pmu.enable;
> +
> + if (i915_seqno_passed(intel_engine_get_seqno(engine),
> + intel_engine_last_submit(engine)))
> + continue;
> +
> + if (enable & BIT(I915_SAMPLE_QUEUED))
> + engine->pmu.sample[I915_SAMPLE_QUEUED] += PERIOD;
> +
> + if (enable & BIT(I915_SAMPLE_BUSY)) {
> + u32 val;
> +
> + fw = grab_forcewake(dev_priv, fw);
> + val = I915_READ_FW(RING_MI_MODE(engine->mmio_base));
> + if (!(val & MODE_IDLE))
> + engine->pmu.sample[I915_SAMPLE_BUSY] += PERIOD;
> + }
> +
> + if (enable & (BIT(I915_SAMPLE_WAIT) | BIT(I915_SAMPLE_SEMA))) {
> + u32 val;
> +
> + fw = grab_forcewake(dev_priv, fw);
> + val = I915_READ_FW(RING_CTL(engine->mmio_base));
> + if ((enable & BIT(I915_SAMPLE_WAIT)) &&
> + (val & RING_WAIT))
> + engine->pmu.sample[I915_SAMPLE_WAIT] += PERIOD;
> + if ((enable & BIT(I915_SAMPLE_SEMA)) &&
> + (val & RING_WAIT_SEMAPHORE))
> + engine->pmu.sample[I915_SAMPLE_SEMA] += PERIOD;
> + }
> + }
> +
> + if (fw)
> + intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
> + intel_runtime_pm_put(dev_priv);
> +}
> +
> +static void frequency_sample(struct drm_i915_private *dev_priv)
> +{
> + if (dev_priv->pmu.enable &
> + config_enabled_mask(I915_PMU_ACTUAL_FREQUENCY)) {
> + u64 val;
> +
> + val = dev_priv->rps.cur_freq;
> + if (dev_priv->gt.awake &&
> + intel_runtime_pm_get_if_in_use(dev_priv)) {
> + val = intel_get_cagf(dev_priv,
> + I915_READ_NOTRACE(GEN6_RPSTAT1));
> + intel_runtime_pm_put(dev_priv);
> + }
> + val = intel_gpu_freq(dev_priv, val);
> + dev_priv->pmu.sample[__I915_SAMPLE_FREQ_ACT] += val * PERIOD;
> + }
> +
> + if (dev_priv->pmu.enable &
> + config_enabled_mask(I915_PMU_REQUESTED_FREQUENCY)) {
> + u64 val = intel_gpu_freq(dev_priv, dev_priv->rps.cur_freq);
> + dev_priv->pmu.sample[__I915_SAMPLE_FREQ_REQ] += val * PERIOD;
> + }
> +}
> +
> +static enum hrtimer_restart i915_sample(struct hrtimer *hrtimer)
> +{
> + struct drm_i915_private *i915 =
> + container_of(hrtimer, struct drm_i915_private, pmu.timer);
> +
> + if (i915->pmu.enable == 0)
> + return HRTIMER_NORESTART;
> +
> + engines_sample(i915);
> + frequency_sample(i915);
> +
> + hrtimer_forward_now(hrtimer, ns_to_ktime(PERIOD));
> + return HRTIMER_RESTART;
> +}
> +
> +static u64 count_interrupts(struct drm_i915_private *i915)
> +{
> + /* open-coded kstat_irqs() */
> + struct irq_desc *desc = irq_to_desc(i915->drm.pdev->irq);
> + u64 sum = 0;
> + int cpu;
> +
> + if (!desc || !desc->kstat_irqs)
> + return 0;
> +
> + for_each_possible_cpu(cpu)
> + sum += *per_cpu_ptr(desc->kstat_irqs, cpu);
> +
> + return sum;
> +}
> +
> +static void i915_pmu_event_destroy(struct perf_event *event)
> +{
> + WARN_ON(event->parent);
> +}
> +
> +static int engine_event_init(struct perf_event *event)
> +{
> + struct drm_i915_private *i915 =
> + container_of(event->pmu, typeof(*i915), pmu.base);
> +
> + if (!intel_engine_lookup_user(i915, engine_event_class(event),
> + engine_event_instance(event)))
> + return -ENODEV;
> +
> + switch (engine_event_sample(event)) {
> + case I915_SAMPLE_QUEUED:
> + case I915_SAMPLE_BUSY:
> + case I915_SAMPLE_WAIT:
> + break;
> + case I915_SAMPLE_SEMA:
> + if (INTEL_GEN(i915) < 6)
> + return -ENODEV;
> + break;
> + default:
> + return -ENOENT;
> + }
> +
> + return 0;
> +}
> +
> +static int i915_pmu_event_init(struct perf_event *event)
> +{
> + struct drm_i915_private *i915 =
> + container_of(event->pmu, typeof(*i915), pmu.base);
> + int cpu, ret;
> +
> + if (event->attr.type != event->pmu->type)
> + return -ENOENT;
> +
> + /* unsupported modes and filters */
> + if (event->attr.sample_period) /* no sampling */
> + return -EINVAL;
> +
> + if (has_branch_stack(event))
> + return -EOPNOTSUPP;
> +
> + if (event->cpu < 0)
> + return -EINVAL;
> +
> + cpu = cpumask_any_and(&i915_pmu_cpumask,
> + topology_sibling_cpumask(event->cpu));
> + if (cpu >= nr_cpu_ids)
> + return -ENODEV;
> +
> + ret = 0;
> + if (is_engine_event(event)) {
> + ret = engine_event_init(event);
> + } else switch (event->attr.config) {
> + case I915_PMU_ACTUAL_FREQUENCY:
> + if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915))
> + ret = -ENODEV; /* requires a mutex for sampling! */
> + case I915_PMU_REQUESTED_FREQUENCY:
> + case I915_PMU_ENERGY:
> + case I915_PMU_RC6_RESIDENCY:
> + case I915_PMU_RC6p_RESIDENCY:
> + case I915_PMU_RC6pp_RESIDENCY:
> + if (INTEL_GEN(i915) < 6)
> + ret = -ENODEV;
> + break;
> + }
> + if (ret)
> + return ret;
> +
> + event->cpu = cpu;
> + if (!event->parent)
> + event->destroy = i915_pmu_event_destroy;
> +
> + return 0;
> +}
> +
> +static u64 __i915_pmu_event_read(struct perf_event *event)
> +{
> + struct drm_i915_private *i915 =
> + container_of(event->pmu, typeof(*i915), pmu.base);
> + u64 val = 0;
> +
> + if (is_engine_event(event)) {
> + u8 sample = engine_event_sample(event);
> + struct intel_engine_cs *engine;
> +
> + engine = intel_engine_lookup_user(i915,
> + engine_event_class(event),
> + engine_event_instance(event));
> +
> + if (WARN_ON_ONCE(!engine)) {
> + /* Do nothing */
> + } else {
> + val = engine->pmu.sample[sample];
> + }
> + } else switch (event->attr.config) {
> + case I915_PMU_ACTUAL_FREQUENCY:
> + val = i915->pmu.sample[__I915_SAMPLE_FREQ_ACT];
> + break;
> + case I915_PMU_REQUESTED_FREQUENCY:
> + val = i915->pmu.sample[__I915_SAMPLE_FREQ_REQ];
> + break;
> + case I915_PMU_ENERGY:
> + val = intel_energy_uJ(i915);
> + break;
> + case I915_PMU_INTERRUPTS:
> + val = count_interrupts(i915);
> + break;
> + case I915_PMU_RC6_RESIDENCY:
> + val = intel_rc6_residency_ns(i915,
> + IS_VALLEYVIEW(i915) ?
> + VLV_GT_RENDER_RC6 :
> + GEN6_GT_GFX_RC6);
> + break;
> + case I915_PMU_RC6p_RESIDENCY:
> + if (!IS_VALLEYVIEW(i915))
> + val = intel_rc6_residency_ns(i915, GEN6_GT_GFX_RC6p);
> + break;
> + case I915_PMU_RC6pp_RESIDENCY:
> + if (!IS_VALLEYVIEW(i915))
> + val = intel_rc6_residency_ns(i915, GEN6_GT_GFX_RC6pp);
> + break;
> + }
> +
> + return val;
> +}
> +
> +static void i915_pmu_event_read(struct perf_event *event)
> +{
> +
> + local64_set(&event->count,
> + __i915_pmu_event_read(event) -
> + local64_read(&event->hw.prev_count));
> +}
> +
> +static void i915_pmu_enable(struct perf_event *event)
> +{
> + struct drm_i915_private *i915 =
> + container_of(event->pmu, typeof(*i915), pmu.base);
> + unsigned int bit = event_enabled_bit(event);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&i915->pmu.lock, flags);
> +
> + /*
> + * Start the sampling timer when enabling the first event.
> + */
> + if (i915->pmu.enable == 0)
> + hrtimer_start_range_ns(&i915->pmu.timer,
> + ns_to_ktime(PERIOD), 0,
> + HRTIMER_MODE_REL_PINNED);
> +
> + /*
> + * Update the bitmask of enabled events and increment
> + * the event reference counter.
> + */
> + GEM_BUG_ON(bit >= I915_PMU_MASK_BITS);
> + GEM_BUG_ON(i915->pmu.enable_count[bit] == ~0);
> + i915->pmu.enable |= BIT_ULL(bit);
> + i915->pmu.enable_count[bit]++;
> +
> + /*
> + * For per-engine events the bitmask and reference counting
> + * is stored per engine.
> + */
> + if (is_engine_event(event)) {
> + u8 sample = engine_event_sample(event);
> + struct intel_engine_cs *engine;
> +
> + engine = intel_engine_lookup_user(i915,
> + engine_event_class(event),
> + engine_event_instance(event));
> + GEM_BUG_ON(!engine);
> + engine->pmu.enable |= BIT(sample);
> +
> + GEM_BUG_ON(sample >= I915_PMU_SAMPLE_BITS);
> + GEM_BUG_ON(engine->pmu.enable_count[sample] == ~0);
> + engine->pmu.enable_count[sample]++;
> + }
> +
> + /*
> + * Store the current counter value so we can report the correct delta
> + * for all listeners. Even when the event was already enabled and has
> + * an existing non-zero value.
> + */
> + local64_set(&event->hw.prev_count, __i915_pmu_event_read(event));
> +
> + spin_unlock_irqrestore(&i915->pmu.lock, flags);
> +}
> +
> +static void i915_pmu_disable(struct perf_event *event)
> +{
> + struct drm_i915_private *i915 =
> + container_of(event->pmu, typeof(*i915), pmu.base);
> + unsigned int bit = event_enabled_bit(event);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&i915->pmu.lock, flags);
> +
> + if (is_engine_event(event)) {
> + u8 sample = engine_event_sample(event);
> + struct intel_engine_cs *engine;
> +
> + engine = intel_engine_lookup_user(i915,
> + engine_event_class(event),
> + engine_event_instance(event));
> + GEM_BUG_ON(!engine);
> + GEM_BUG_ON(sample >= I915_PMU_SAMPLE_BITS);
> + GEM_BUG_ON(engine->pmu.enable_count[sample] == 0);
> + /*
> + * Decrement the reference count and clear the enabled
> + * bitmask when the last listener on an event goes away.
> + */
> + if (--engine->pmu.enable_count[sample] == 0)
> + engine->pmu.enable &= ~BIT(sample);
> + }
> +
> + GEM_BUG_ON(bit >= I915_PMU_MASK_BITS);
> + GEM_BUG_ON(i915->pmu.enable_count[bit] == 0);
> + /*
> + * Decrement the reference count and clear the enabled
> + * bitmask when the last listener on an event goes away.
> + */
> + if (--i915->pmu.enable_count[bit] == 0)
> + i915->pmu.enable &= ~BIT_ULL(bit);
> +
> + spin_unlock_irqrestore(&i915->pmu.lock, flags);
> +}
> +
> +static void i915_pmu_event_start(struct perf_event *event, int flags)
> +{
> + i915_pmu_enable(event);
> + event->hw.state = 0;
> +}
> +
> +static void i915_pmu_event_stop(struct perf_event *event, int flags)
> +{
> + if (flags & PERF_EF_UPDATE)
> + i915_pmu_event_read(event);
> + i915_pmu_disable(event);
> + event->hw.state = PERF_HES_STOPPED;
> +}
> +
> +static int i915_pmu_event_add(struct perf_event *event, int flags)
> +{
> + if (flags & PERF_EF_START)
> + i915_pmu_event_start(event, flags);
> +
> + return 0;
> +}
> +
> +static void i915_pmu_event_del(struct perf_event *event, int flags)
> +{
> + i915_pmu_event_stop(event, PERF_EF_UPDATE);
> +}
> +
> +static int i915_pmu_event_event_idx(struct perf_event *event)
> +{
> + return 0;
> +}
> +
> +static ssize_t i915_pmu_format_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct dev_ext_attribute *eattr;
> +
> + eattr = container_of(attr, struct dev_ext_attribute, attr);
> + return sprintf(buf, "%s\n", (char *) eattr->var);
> +}
> +
> +#define I915_PMU_FORMAT_ATTR(_name, _config) \
> + (&((struct dev_ext_attribute[]) { \
> + { .attr = __ATTR(_name, S_IRUGO, i915_pmu_format_show, NULL), \
> + .var = (void *) _config, } \
> + })[0].attr.attr)
> +
> +static struct attribute *i915_pmu_format_attrs[] = {
> + I915_PMU_FORMAT_ATTR(i915_eventid, "config:0-42"),
> + NULL,
> +};
> +
> +static const struct attribute_group i915_pmu_format_attr_group = {
> + .name = "format",
> + .attrs = i915_pmu_format_attrs,
> +};
> +
> +static ssize_t i915_pmu_event_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct dev_ext_attribute *eattr;
> +
> + eattr = container_of(attr, struct dev_ext_attribute, attr);
> + return sprintf(buf, "config=0x%lx\n", (unsigned long) eattr->var);
> +}
> +
> +#define I915_PMU_EVENT_ATTR(_name, _config) \
> + (&((struct dev_ext_attribute[]) { \
> + { .attr = __ATTR(_name, S_IRUGO, i915_pmu_event_show, NULL), \
> + .var = (void *) _config, } \
> + })[0].attr.attr)
> +
> +static struct attribute *i915_pmu_events_attrs[] = {
> + I915_PMU_EVENT_ATTR(rcs0-queued,
> + I915_PMU_ENGINE_QUEUED(I915_ENGINE_CLASS_RENDER, 0)),
> + I915_PMU_EVENT_ATTR(rcs0-busy,
> + I915_PMU_ENGINE_BUSY(I915_ENGINE_CLASS_RENDER, 0)),
> + I915_PMU_EVENT_ATTR(rcs0-wait,
> + I915_PMU_ENGINE_WAIT(I915_ENGINE_CLASS_RENDER, 0)),
> + I915_PMU_EVENT_ATTR(rcs0-sema,
> + I915_PMU_ENGINE_SEMA(I915_ENGINE_CLASS_RENDER, 0)),
> +
> + I915_PMU_EVENT_ATTR(bcs0-queued,
> + I915_PMU_ENGINE_QUEUED(I915_ENGINE_CLASS_COPY, 0)),
> + I915_PMU_EVENT_ATTR(bcs0-busy,
> + I915_PMU_ENGINE_BUSY(I915_ENGINE_CLASS_COPY, 0)),
> + I915_PMU_EVENT_ATTR(bcs0-wait,
> + I915_PMU_ENGINE_WAIT(I915_ENGINE_CLASS_COPY, 0)),
> + I915_PMU_EVENT_ATTR(bcs0-sema,
> + I915_PMU_ENGINE_SEMA(I915_ENGINE_CLASS_COPY, 0)),
> +
> + I915_PMU_EVENT_ATTR(vcs0-queued,
> + I915_PMU_ENGINE_QUEUED(I915_ENGINE_CLASS_VIDEO, 0)),
> + I915_PMU_EVENT_ATTR(vcs0-busy,
> + I915_PMU_ENGINE_BUSY(I915_ENGINE_CLASS_VIDEO, 0)),
> + I915_PMU_EVENT_ATTR(vcs0-wait,
> + I915_PMU_ENGINE_WAIT(I915_ENGINE_CLASS_VIDEO, 0)),
> + I915_PMU_EVENT_ATTR(vcs0-sema,
> + I915_PMU_ENGINE_SEMA(I915_ENGINE_CLASS_VIDEO, 0)),
> +
> + I915_PMU_EVENT_ATTR(vcs1-queued,
> + I915_PMU_ENGINE_QUEUED(I915_ENGINE_CLASS_VIDEO, 1)),
> + I915_PMU_EVENT_ATTR(vcs1-busy,
> + I915_PMU_ENGINE_BUSY(I915_ENGINE_CLASS_VIDEO, 1)),
> + I915_PMU_EVENT_ATTR(vcs1-wait,
> + I915_PMU_ENGINE_WAIT(I915_ENGINE_CLASS_VIDEO, 1)),
> + I915_PMU_EVENT_ATTR(vcs1-sema,
> + I915_PMU_ENGINE_SEMA(I915_ENGINE_CLASS_VIDEO, 1)),
> +
> + I915_PMU_EVENT_ATTR(vecs0-queued,
> + I915_PMU_ENGINE_QUEUED(I915_ENGINE_CLASS_VIDEO_ENHANCE, 0)),
> + I915_PMU_EVENT_ATTR(vecs0-busy,
> + I915_PMU_ENGINE_BUSY(I915_ENGINE_CLASS_VIDEO_ENHANCE, 0)),
> + I915_PMU_EVENT_ATTR(vecs0-wait,
> + I915_PMU_ENGINE_WAIT(I915_ENGINE_CLASS_VIDEO_ENHANCE, 0)),
> + I915_PMU_EVENT_ATTR(vecs0-sema,
> + I915_PMU_ENGINE_SEMA(I915_ENGINE_CLASS_VIDEO_ENHANCE, 0)),
> +
> + I915_PMU_EVENT_ATTR(actual-frequency, I915_PMU_ACTUAL_FREQUENCY),
> + I915_PMU_EVENT_ATTR(requested-frequency, I915_PMU_REQUESTED_FREQUENCY),
> + I915_PMU_EVENT_ATTR(energy, I915_PMU_ENERGY),
> + I915_PMU_EVENT_ATTR(interrupts, I915_PMU_INTERRUPTS),
> + I915_PMU_EVENT_ATTR(rc6-residency, I915_PMU_RC6_RESIDENCY),
> + I915_PMU_EVENT_ATTR(rc6p-residency, I915_PMU_RC6p_RESIDENCY),
> + I915_PMU_EVENT_ATTR(rc6pp-residency, I915_PMU_RC6pp_RESIDENCY),
> +
> + NULL,
> +};
> +
> +static const struct attribute_group i915_pmu_events_attr_group = {
> + .name = "events",
> + .attrs = i915_pmu_events_attrs,
> +};
> +
> +static ssize_t
> +i915_pmu_get_attr_cpumask(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + return cpumap_print_to_pagebuf(true, buf, &i915_pmu_cpumask);
> +}
> +
> +static DEVICE_ATTR(cpumask, S_IRUGO, i915_pmu_get_attr_cpumask, NULL);
> +
> +static struct attribute *i915_cpumask_attrs[] = {
> + &dev_attr_cpumask.attr,
> + NULL,
> +};
> +
> +static struct attribute_group i915_pmu_cpumask_attr_group = {
> + .attrs = i915_cpumask_attrs,
> +};
> +
> +static const struct attribute_group *i915_pmu_attr_groups[] = {
> + &i915_pmu_format_attr_group,
> + &i915_pmu_events_attr_group,
> + &i915_pmu_cpumask_attr_group,
> + NULL
> +};
> +
> +static int i915_pmu_cpu_online(unsigned int cpu, struct hlist_node *node)
> +{
> + unsigned int target;
> +
> + target = cpumask_any_and(&i915_pmu_cpumask, &i915_pmu_cpumask);
> + /* Select the first online CPU as a designated reader. */
> + if (target >= nr_cpu_ids)
> + cpumask_set_cpu(cpu, &i915_pmu_cpumask);
> +
> + return 0;
> +}
> +
> +static int i915_pmu_cpu_offline(unsigned int cpu, struct hlist_node *node)
> +{
> + struct i915_pmu *pmu = hlist_entry_safe(node, typeof(*pmu), node);
> + unsigned int target;
> +
> + if (cpumask_test_and_clear_cpu(cpu, &i915_pmu_cpumask)) {
> + target = cpumask_any_but(topology_sibling_cpumask(cpu), cpu);
> + /* Migrate events if there is a valid target */
> + if (target < nr_cpu_ids) {
> + cpumask_set_cpu(target, &i915_pmu_cpumask);
> + perf_pmu_migrate_context(&pmu->base, cpu, target);
> + }
> + }
> +
> + return 0;
> +}
> +
> +void i915_pmu_register(struct drm_i915_private *i915)
> +{
> + int ret = ENOTSUPP;
> +
> + if (INTEL_GEN(i915) <= 2)
> + goto err;
> +
> + ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_X86_UNCORE_ONLINE,
> + "perf/x86/intel/i915:online",
> + i915_pmu_cpu_online,
> + i915_pmu_cpu_offline);
> + if (ret)
> + goto err;
> +
> + ret = cpuhp_state_add_instance(CPUHP_AP_PERF_X86_UNCORE_ONLINE,
> + &i915->pmu.node);
> + if (ret)
> + goto err;
> +
> + i915->pmu.base.attr_groups = i915_pmu_attr_groups;
> + i915->pmu.base.task_ctx_nr = perf_invalid_context;
> + i915->pmu.base.event_init = i915_pmu_event_init;
> + i915->pmu.base.add = i915_pmu_event_add;
> + i915->pmu.base.del = i915_pmu_event_del;
> + i915->pmu.base.start = i915_pmu_event_start;
> + i915->pmu.base.stop = i915_pmu_event_stop;
> + i915->pmu.base.read = i915_pmu_event_read;
> + i915->pmu.base.event_idx = i915_pmu_event_event_idx;
> +
> + spin_lock_init(&i915->pmu.lock);
> + hrtimer_init(&i915->pmu.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> + i915->pmu.timer.function = i915_sample;
> + i915->pmu.enable = 0;
> +
> + if (perf_pmu_register(&i915->pmu.base, "i915", -1))
> + i915->pmu.base.event_init = NULL;
> +
> +err:
> + DRM_INFO("Failed to register PMU (err=%d)\n", ret);
> +}
> +
> +void i915_pmu_unregister(struct drm_i915_private *i915)
> +{
> + if (!i915->pmu.base.event_init)
> + return;
> +
> + i915->pmu.enable = 0;
> +
> + perf_pmu_unregister(&i915->pmu.base);
> + i915->pmu.base.event_init = NULL;
> +
> + hrtimer_cancel(&i915->pmu.timer);
> +
> + cpuhp_state_remove_instance(CPUHP_AP_PERF_X86_UNCORE_ONLINE,
> + &i915->pmu.node);
> +}
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 0b03260a3967..8c362e0451c1 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -186,6 +186,9 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
> #define VIDEO_ENHANCEMENT_CLASS 2
> #define COPY_ENGINE_CLASS 3
> #define OTHER_CLASS 4
> +#define MAX_ENGINE_CLASS 4
> +
> +#define MAX_ENGINE_INSTANCE 1
>
> /* PCI config space */
>
> diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
> index 3ae89a9d6241..dbc7abd65f33 100644
> --- a/drivers/gpu/drm/i915/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/intel_engine_cs.c
> @@ -198,6 +198,15 @@ intel_engine_setup(struct drm_i915_private *dev_priv,
> GEM_BUG_ON(info->class >= ARRAY_SIZE(intel_engine_classes));
> class_info = &intel_engine_classes[info->class];
>
> + if (GEM_WARN_ON(info->class > MAX_ENGINE_CLASS))
> + return -EINVAL;
> +
> + if (GEM_WARN_ON(info->instance > MAX_ENGINE_INSTANCE))
> + return -EINVAL;
> +
> + if (GEM_WARN_ON(dev_priv->engine_class[info->class][info->instance]))
> + return -EINVAL;
> +
> GEM_BUG_ON(dev_priv->engine[id]);
> engine = kzalloc(sizeof(*engine), GFP_KERNEL);
> if (!engine)
> @@ -225,6 +234,7 @@ intel_engine_setup(struct drm_i915_private *dev_priv,
>
> ATOMIC_INIT_NOTIFIER_HEAD(&engine->context_status_notifier);
>
> + dev_priv->engine_class[info->class][info->instance] = engine;
> dev_priv->engine[id] = engine;
> return 0;
> }
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index 268342433a8e..7db4c572ef76 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -2283,3 +2283,28 @@ int intel_init_vebox_ring_buffer(struct intel_engine_cs *engine)
>
> return intel_init_ring_buffer(engine);
> }
> +
> +static u8 user_class_map[I915_ENGINE_CLASS_MAX] = {
> + [I915_ENGINE_CLASS_OTHER] = OTHER_CLASS,
> + [I915_ENGINE_CLASS_RENDER] = RENDER_CLASS,
> + [I915_ENGINE_CLASS_COPY] = COPY_ENGINE_CLASS,
> + [I915_ENGINE_CLASS_VIDEO] = VIDEO_DECODE_CLASS,
> + [I915_ENGINE_CLASS_VIDEO_ENHANCE] = VIDEO_ENHANCEMENT_CLASS,
> +};
> +
> +struct intel_engine_cs *
> +intel_engine_lookup_user(struct drm_i915_private *i915, u8 class, u8 instance)
> +{
> + if (class >= ARRAY_SIZE(user_class_map))
> + return NULL;
> +
> + class = user_class_map[class];
> +
> + if (WARN_ON_ONCE(class > MAX_ENGINE_CLASS))
> + return NULL;
> +
> + if (instance > MAX_ENGINE_INSTANCE)
> + return NULL;
> +
> + return i915->engine_class[class][instance];
> +}
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index 79c0021f3700..cf095b9386f4 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -245,6 +245,28 @@ struct intel_engine_cs {
> I915_SELFTEST_DECLARE(bool mock : 1);
> } breadcrumbs;
>
> + struct {
> + /**
> + * @enable: Bitmask of enable sample events on this engine.
> + *
> + * Bits correspond to sample event types, for instance
> + * I915_SAMPLE_QUEUED is bit 0 etc.
> + */
> + u32 enable;
> + /**
> + * @enable_count: Reference count for the enabled samplers.
> + *
> + * Index number corresponds to the bit number from @enable.
> + */
> + unsigned int enable_count[I915_PMU_SAMPLE_BITS];
> + /**
> + * @sample: Counter value for sampling events.
> + *
> + * Our internal timer stores the current counter in this field.
> + */
> + u64 sample[I915_ENGINE_SAMPLE_MAX];
> + } pmu;
> +
> /*
> * A pool of objects to use as shadow copies of client batch buffers
> * when the command parser is enabled. Prevents the client from
> @@ -737,4 +759,7 @@ void intel_engines_reset_default_submission(struct drm_i915_private *i915);
>
> bool intel_engine_can_store_dword(struct intel_engine_cs *engine);
>
> +struct intel_engine_cs *
> +intel_engine_lookup_user(struct drm_i915_private *i915, u8 class, u8 instance);
> +
> #endif /* _INTEL_RINGBUFFER_H_ */
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index d8d10d932759..6dc0d6fd4e4c 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -86,6 +86,64 @@ enum i915_mocs_table_index {
> I915_MOCS_CACHED,
> };
>
> +enum drm_i915_gem_engine_class {
> + I915_ENGINE_CLASS_OTHER = 0,
> + I915_ENGINE_CLASS_RENDER = 1,
> + I915_ENGINE_CLASS_COPY = 2,
> + I915_ENGINE_CLASS_VIDEO = 3,
> + I915_ENGINE_CLASS_VIDEO_ENHANCE = 4,
> + I915_ENGINE_CLASS_MAX /* non-ABI */
> +};
> +
> +/**
> + * DOC: perf_events exposed by i915 through /sys/bus/event_sources/drivers/i915
> + *
> + */
> +
> +enum drm_i915_pmu_engine_sample {
> + I915_SAMPLE_QUEUED = 0,
> + I915_SAMPLE_BUSY = 1,
> + I915_SAMPLE_WAIT = 2,
> + I915_SAMPLE_SEMA = 3,
> + I915_ENGINE_SAMPLE_MAX /* non-ABI */
> +};
> +
> +#define I915_PMU_SAMPLE_BITS (4)
> +#define I915_PMU_SAMPLE_MASK (0xf)
> +#define I915_PMU_SAMPLE_INSTANCE_BITS (8)
> +#define I915_PMU_CLASS_SHIFT \
> + (I915_PMU_SAMPLE_BITS + I915_PMU_SAMPLE_INSTANCE_BITS)
> +
> +#define __I915_PMU_ENGINE(class, instance, sample) \
> + ((class) << I915_PMU_CLASS_SHIFT | \
> + (instance) << I915_PMU_SAMPLE_BITS | \
> + (sample))
> +
> +#define I915_PMU_ENGINE_QUEUED(class, instance) \
> + __I915_PMU_ENGINE(class, instance, I915_SAMPLE_QUEUED)
> +
> +#define I915_PMU_ENGINE_BUSY(class, instance) \
> + __I915_PMU_ENGINE(class, instance, I915_SAMPLE_BUSY)
> +
> +#define I915_PMU_ENGINE_WAIT(class, instance) \
> + __I915_PMU_ENGINE(class, instance, I915_SAMPLE_WAIT)
> +
> +#define I915_PMU_ENGINE_SEMA(class, instance) \
> + __I915_PMU_ENGINE(class, instance, I915_SAMPLE_SEMA)
> +
> +#define __I915_PMU_OTHER(x) (__I915_PMU_ENGINE(0xff, 0xff, 0xf) + 1 + (x))
> +
> +#define I915_PMU_ACTUAL_FREQUENCY __I915_PMU_OTHER(0)
> +#define I915_PMU_REQUESTED_FREQUENCY __I915_PMU_OTHER(1)
> +#define I915_PMU_ENERGY __I915_PMU_OTHER(2)
> +#define I915_PMU_INTERRUPTS __I915_PMU_OTHER(3)
> +
> +#define I915_PMU_RC6_RESIDENCY __I915_PMU_OTHER(4)
> +#define I915_PMU_RC6p_RESIDENCY __I915_PMU_OTHER(5)
> +#define I915_PMU_RC6pp_RESIDENCY __I915_PMU_OTHER(6)
> +
> +#define I915_PMU_LAST I915_PMU_RC6pp_RESIDENCY
> +
> /* Each region is a minimum of 16k, and there are at most 255 of them.
> */
> #define I915_NR_TEX_REGIONS 255 /* table size 2k - maximum due to use
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