[PATCH v7 3/3] drm/xe/pmu: Add GT frequency events
Vinay Belgaumkar
vinay.belgaumkar at intel.com
Wed Nov 13 23:27:00 UTC 2024
Define PMU events for GT frequency (actual and requested). This is
a port from the i915 driver implementation, where an internal timer
is used to aggregate GT frequencies over certain fixed interval.
Following PMU events are being added-
xe_0000_00_02.0/actual-frequency-gt0/ [Kernel PMU event]
xe_0000_00_02.0/actual-frequency-gt1/ [Kernel PMU event]
xe_0000_00_02.0/requested-frequency-gt0/ [Kernel PMU event]
xe_0000_00_02.0/requested-frequency-gt1/ [Kernel PMU event]
Standard perf commands can be used to monitor GT frequency-
$ perf stat -e xe_0000_00_02.0/requested-frequency-gt0/ -I1000
1.001175175 700 M xe/requested-frequency-gt0/
2.005891881 703 M xe/requested-frequency-gt0/
3.007318169 700 M xe/requested-frequency-gt0/
Actual/requested frequencies will be 0 when GT is suspended.
v2: Checkpatch fix, moved timer code to this patch
v3: Fix kunit issue
v4: Checkpatch warning fixes
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
---
drivers/gpu/drm/xe/xe_gt.c | 2 +
drivers/gpu/drm/xe/xe_pmu.c | 248 +++++++++++++++++++++++++++++-
drivers/gpu/drm/xe/xe_pmu.h | 2 +
drivers/gpu/drm/xe/xe_pmu_types.h | 26 ++++
4 files changed, 277 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
index fd18bbce99da..ef27db83c09c 100644
--- a/drivers/gpu/drm/xe/xe_gt.c
+++ b/drivers/gpu/drm/xe/xe_gt.c
@@ -940,6 +940,8 @@ int xe_gt_resume(struct xe_gt *gt)
xe_gt_idle_enable_pg(gt);
+ xe_pmu_resume(gt);
+
xe_force_wake_put(gt_to_fw(gt), fw_ref);
xe_gt_dbg(gt, "resumed\n");
diff --git a/drivers/gpu/drm/xe/xe_pmu.c b/drivers/gpu/drm/xe/xe_pmu.c
index 199344154408..633552fbf78d 100644
--- a/drivers/gpu/drm/xe/xe_pmu.c
+++ b/drivers/gpu/drm/xe/xe_pmu.c
@@ -63,6 +63,31 @@ static unsigned int xe_pmu_target_cpu = -1;
* 2352945
*
* Each value is roughly a 1000ms increment here as well. This is expected GT residency when idle.
+ *
+ * PMU frequency events use a software timer to aggregate GT freq values over the time of capture.
+ * This allows us to calculate a rough average over the timespan. This is why sysfs is the best way
+ * to obtain instantaneous frequency if accuracy is intended. Advantage of using PMU is that it
+ * results in lesser CPU utilization as compared to dumping sysfs entries repeatedly.
+ *
+ * To list GT frequency events, use the following-
+ *
+ * $ perf list | grep frequency-gt
+ * xe_0000_00_02.0/actual-frequency-gt0/ [Kernel PMU event]
+ * xe_0000_00_02.0/actual-frequency-gt1/ [Kernel PMU event]
+ * xe_0000_00_02.0/requested-frequency-gt0/ [Kernel PMU event]
+ * xe_0000_00_02.0/requested-frequency-gt1/ [Kernel PMU event]
+ *
+ * $ perf stat -e xe_0000_00_02.0/requested-frequency-gt0/ -I1000
+ * # time counts unit events
+ * 1.001189056 1950 M xe_0000_00_02.0/requested-frequency-gt0/
+ * 2.006388494 1960 M xe_0000_00_02.0/requested-frequency-gt0/
+ * 3.007930311 1959 M xe_0000_00_02.0/requested-frequency-gt0/
+ *
+ * Dumping requested freq from sysfs-
+ * $ while true; do cat /sys/class/drm/card0/device/tile0/gt0/freq0/cur_freq ; sleep 1; done
+ * 1950
+ * 1950
+ * 1950
*/
static struct xe_pmu *event_to_pmu(struct perf_event *event)
@@ -88,6 +113,12 @@ static unsigned int other_bit(const u64 config)
case XE_PMU_RC6_RESIDENCY:
val = __XE_PMU_RC6_RESIDENCY_ENABLED;
break;
+ case XE_PMU_ACTUAL_FREQUENCY:
+ val = __XE_PMU_ACTUAL_FREQUENCY_ENABLED;
+ break;
+ case XE_PMU_REQUESTED_FREQUENCY:
+ val = __XE_PMU_REQUESTED_FREQUENCY_ENABLED;
+ break;
default:
/*
* Events that do not require sampling, or tracking state
@@ -104,6 +135,22 @@ static unsigned int config_bit(const u64 config)
return other_bit(config);
}
+static u32 config_mask(const u64 config)
+{
+ unsigned int bit = config_bit(config);
+
+ if (__builtin_constant_p(config))
+ BUILD_BUG_ON(bit >
+ BITS_PER_TYPE(typeof_member(struct xe_pmu,
+ enable)) - 1);
+ else
+ WARN_ON_ONCE(bit >
+ BITS_PER_TYPE(typeof_member(struct xe_pmu,
+ enable)) - 1);
+
+ return BIT(config_bit(config));
+}
+
static unsigned int event_bit(struct perf_event *event)
{
return config_bit(event->attr.config);
@@ -132,6 +179,10 @@ config_status(struct xe_device *xe, u64 config)
if (xe->info.skip_guc_pc)
return -ENODEV;
break;
+ case XE_PMU_ACTUAL_FREQUENCY:
+ fallthrough;
+ case XE_PMU_REQUESTED_FREQUENCY:
+ break;
default:
return -ENOENT;
}
@@ -194,6 +245,12 @@ store_sample(struct xe_pmu *pmu, unsigned int gt_id, int sample, u64 val)
pmu->event_sample[gt_id][sample].cur = val;
}
+static void
+add_sample_mult(struct xe_pmu *pmu, unsigned int gt_id, int sample, u32 val, u32 mul)
+{
+ pmu->event_sample[gt_id][sample].cur += mul_u32_u32(val, mul);
+}
+
static u64 get_rc6(struct xe_gt *gt)
{
struct xe_device *xe = gt_to_xe(gt);
@@ -239,6 +296,7 @@ static u64 __xe_pmu_event_read(struct perf_event *event)
{
struct xe_device *xe =
container_of(event->pmu, typeof(*xe), pmu.base);
+ struct xe_pmu *pmu = &xe->pmu;
const unsigned int gt_id = config_gt_id(event->attr.config);
const u64 config = event->attr.config;
struct xe_gt *gt = xe_device_get_gt(xe, gt_id);
@@ -248,6 +306,18 @@ static u64 __xe_pmu_event_read(struct perf_event *event)
case XE_PMU_RC6_RESIDENCY:
val = get_rc6(gt);
break;
+ case XE_PMU_ACTUAL_FREQUENCY:
+ val =
+ div_u64(read_sample(pmu, gt_id,
+ __XE_SAMPLE_FREQ_ACT),
+ USEC_PER_SEC /* to MHz */);
+ break;
+ case XE_PMU_REQUESTED_FREQUENCY:
+ val =
+ div_u64(read_sample(pmu, gt_id,
+ __XE_SAMPLE_FREQ_REQ),
+ USEC_PER_SEC /* to MHz */);
+ break;
default:
drm_warn(>->tile->xe->drm, "unknown pmu event\n");
}
@@ -277,6 +347,144 @@ static void xe_pmu_event_read(struct perf_event *event)
local64_add(new - prev, &event->count);
}
+static u32 frequency_enabled_mask(void)
+{
+ unsigned int i;
+ u32 mask = 0;
+
+ for (i = 0; i < XE_PMU_MAX_GT; i++)
+ mask |= config_mask(__XE_PMU_ACTUAL_FREQUENCY(i)) |
+ config_mask(__XE_PMU_REQUESTED_FREQUENCY(i));
+
+ return mask;
+}
+
+static bool
+frequency_sampling_enabled(struct xe_pmu *pmu, unsigned int gt)
+{
+ return pmu->enable &
+ (config_mask(__XE_PMU_ACTUAL_FREQUENCY(gt)) |
+ config_mask(__XE_PMU_REQUESTED_FREQUENCY(gt)));
+}
+
+static void
+frequency_sample(struct xe_gt *gt, unsigned int period_ns)
+{
+ struct xe_device *xe = gt_to_xe(gt);
+ const unsigned int gt_id = gt->info.id;
+ struct xe_pmu *pmu = &xe->pmu;
+ bool device_awake;
+ int ret;
+ u32 cur_freq;
+
+ if (!frequency_sampling_enabled(pmu, gt_id))
+ return;
+
+ /* Report 0/0 (actual/requested) frequency while GT is suspended. */
+ device_awake = xe_pm_runtime_get_if_active(xe);
+ if (!device_awake)
+ return;
+
+ if (pmu->enable & config_mask(__XE_PMU_ACTUAL_FREQUENCY(gt_id))) {
+ u32 val;
+
+ /*
+ * We take a quick peek here without using forcewake
+ * so that we don't perturb the system under observation
+ * (forcewake => !rc6 => increased power use). We expect
+ * that if the read fails because it is outside of the
+ * mmio power well, then it will return 0 -- in which
+ * case we assume the system is running at the intended
+ * frequency. Fortunately, the read should rarely fail!
+ */
+ val = xe_guc_pc_get_act_freq(>->uc.guc.pc);
+
+ add_sample_mult(pmu, gt_id, __XE_SAMPLE_FREQ_ACT,
+ val, period_ns / 1000);
+ }
+
+ if (pmu->enable & config_mask(__XE_PMU_REQUESTED_FREQUENCY(gt_id))) {
+ ret = xe_guc_pc_get_cur_freq(>->uc.guc.pc, &cur_freq);
+ if (!ret)
+ add_sample_mult(pmu, gt_id, __XE_SAMPLE_FREQ_REQ,
+ cur_freq,
+ period_ns / 1000);
+ }
+
+ xe_pm_runtime_put(xe);
+}
+
+static enum hrtimer_restart xe_sample(struct hrtimer *hrtimer)
+{
+ struct xe_pmu *pmu = container_of(hrtimer, struct xe_pmu, timer);
+ struct xe_device *xe = container_of(pmu, typeof(*xe), pmu);
+ u64 period = max_t(u64, 10000, NSEC_PER_SEC / FREQUENCY);
+ unsigned int period_ns;
+ struct xe_gt *gt;
+ unsigned int i;
+ ktime_t now;
+
+ if (!READ_ONCE(pmu->timer_enabled))
+ return HRTIMER_NORESTART;
+
+ now = ktime_get();
+ period_ns = ktime_to_ns(ktime_sub(now, pmu->timer_last));
+ pmu->timer_last = now;
+
+ /*
+ * Strictly speaking the passed in period may not be 100% accurate for
+ * all internal calculation, since some amount of time can be spent on
+ * grabbing the forcewake. However the potential error from timer call-
+ * back delay greatly dominates this so we keep it simple.
+ */
+
+ for_each_gt(gt, xe, i) {
+ if (!(pmu->active_gts & BIT(i)))
+ continue;
+ frequency_sample(gt, period_ns);
+ }
+
+ hrtimer_forward(hrtimer, now, ns_to_ktime(period));
+
+ return HRTIMER_RESTART;
+}
+
+static bool pmu_needs_timer(struct xe_pmu *pmu)
+{
+ u32 enable;
+
+ /*
+ * Only some counters need the sampling timer.
+ *
+ * We start with a bitmask of all currently enabled events.
+ */
+ enable = pmu->enable;
+
+ /*
+ * Mask out all the ones which do not need the timer, or in
+ * other words keep all the ones that could need the timer.
+ */
+ enable &= frequency_enabled_mask();
+
+ /*
+ * If some bits remain it means we need the sampling timer running.
+ */
+ return enable;
+}
+
+static void __xe_pmu_maybe_start_timer(struct xe_pmu *pmu)
+{
+ u64 period = max_t(u64, 10000, NSEC_PER_SEC / FREQUENCY);
+
+ if (!pmu->timer_enabled && pmu_needs_timer(pmu)) {
+ pmu->timer_enabled = true;
+ pmu->timer_last = ktime_get();
+ hrtimer_start_range_ns(&pmu->timer,
+ ns_to_ktime(period), 0,
+ HRTIMER_MODE_REL_PINNED);
+ }
+}
+
static void xe_pmu_enable(struct perf_event *event)
{
struct xe_pmu *pmu = event_to_pmu(event);
@@ -299,6 +507,11 @@ static void xe_pmu_enable(struct perf_event *event)
pmu->enable |= BIT(bit);
pmu->enable_count[bit]++;
+ /*
+ * Start the sampling timer if needed and not already enabled.
+ */
+ __xe_pmu_maybe_start_timer(pmu);
+
spin_unlock_irqrestore(&pmu->lock, flags);
update:
/*
@@ -328,8 +541,10 @@ static void xe_pmu_disable(struct perf_event *event)
* Decrement the reference count and clear the enabled
* bitmask when the last listener on an event goes away.
*/
- if (--pmu->enable_count[bit] == 0)
+ if (--pmu->enable_count[bit] == 0) {
pmu->enable &= ~BIT(bit);
+ pmu->timer_enabled &= pmu_needs_timer(pmu);
+ }
spin_unlock_irqrestore(&pmu->lock, flags);
}
@@ -463,6 +678,8 @@ create_event_attributes(struct xe_pmu *pmu)
const char *unit;
} events[] = {
__event(0, "c6-residency", "ms"),
+ __event(1, "actual-frequency", "M"),
+ __event(2, "requested-frequency", "M"),
};
struct perf_pmu_events_attr *pmu_attr = NULL, *pmu_iter;
@@ -676,6 +893,31 @@ void xe_pmu_suspend(struct xe_gt *gt)
spin_unlock_irq(&pmu->lock);
}
+/**
+ * xe_pmu_resume() - Restart the timer if needed
+ * @gt: GT object
+ */
+void xe_pmu_resume(struct xe_gt *gt)
+{
+ struct xe_device *xe = gt_to_xe(gt);
+ struct xe_pmu *pmu = &xe->pmu;
+
+ if (!pmu->base.event_init)
+ return;
+
+ spin_lock_irq(&pmu->lock);
+
+ /*
+ * Re-enable sampling timer when GPU goes active.
+ */
+ if (pmu->active_gts == 0)
+ __xe_pmu_maybe_start_timer(pmu);
+
+ pmu->active_gts |= BIT(gt->info.id);
+
+ spin_unlock_irq(&pmu->lock);
+}
+
/**
* xe_pmu_unregister() - Remove/cleanup PMU registration
* @arg: Ptr to pmu
@@ -689,6 +931,8 @@ void xe_pmu_unregister(void *arg)
pmu->registered = false;
+ hrtimer_cancel(&pmu->timer);
+
xe_pmu_unregister_cpuhp_state(pmu);
perf_pmu_unregister(&pmu->base);
@@ -732,6 +976,8 @@ void xe_pmu_register(struct xe_pmu *pmu)
int ret = -ENOMEM;
spin_lock_init(&pmu->lock);
+ hrtimer_init(&pmu->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ pmu->timer.function = xe_sample;
pmu->cpuhp.cpu = -1;
pmu->name = kasprintf(GFP_KERNEL,
diff --git a/drivers/gpu/drm/xe/xe_pmu.h b/drivers/gpu/drm/xe/xe_pmu.h
index 17f5a8d7d45c..fb6e3819d7bc 100644
--- a/drivers/gpu/drm/xe/xe_pmu.h
+++ b/drivers/gpu/drm/xe/xe_pmu.h
@@ -16,12 +16,14 @@ void xe_pmu_exit(void);
void xe_pmu_register(struct xe_pmu *pmu);
void xe_pmu_unregister(void *arg);
void xe_pmu_suspend(struct xe_gt *gt);
+void xe_pmu_resume(struct xe_gt *gt);
#else
static inline int xe_pmu_init(void) { return 0; }
static inline void xe_pmu_exit(void) {}
static inline void xe_pmu_register(struct xe_pmu *pmu) {}
static inline void xe_pmu_unregister(void *arg) {}
static inline void xe_pmu_suspend(struct xe_gt *gt) {}
+static inline void xe_pmu_resume(struct xe_gt *gt) {}
#endif
#endif
diff --git a/drivers/gpu/drm/xe/xe_pmu_types.h b/drivers/gpu/drm/xe/xe_pmu_types.h
index 3718bfe7621d..44295747bd5c 100644
--- a/drivers/gpu/drm/xe/xe_pmu_types.h
+++ b/drivers/gpu/drm/xe/xe_pmu_types.h
@@ -12,6 +12,8 @@
enum {
__XE_SAMPLE_RC6,
__XE_SAMPLE_RC6_LAST_REPORTED,
+ __XE_SAMPLE_FREQ_ACT,
+ __XE_SAMPLE_FREQ_REQ,
__XE_NUM_PMU_SAMPLERS
};
@@ -28,13 +30,19 @@ enum {
#define __XE_PMU_OTHER(x) ___XE_PMU_OTHER(0, x)
#define XE_PMU_RC6_RESIDENCY __XE_PMU_OTHER(0)
+#define XE_PMU_ACTUAL_FREQUENCY __XE_PMU_OTHER(1)
+#define XE_PMU_REQUESTED_FREQUENCY __XE_PMU_OTHER(2)
#define __XE_PMU_RC6_RESIDENCY(gt) ___XE_PMU_OTHER(gt, 0)
+#define __XE_PMU_ACTUAL_FREQUENCY(gt) ___XE_PMU_OTHER(gt, 1)
+#define __XE_PMU_REQUESTED_FREQUENCY(gt) ___XE_PMU_OTHER(gt, 2)
/*
* Non-engine events that we need to track enabled-disabled transition and
* current state.
*/
enum xe_pmu_tracked_events {
+ __XE_PMU_ACTUAL_FREQUENCY_ENABLED,
+ __XE_PMU_REQUESTED_FREQUENCY_ENABLED,
__XE_PMU_RC6_RESIDENCY_ENABLED,
__XE_PMU_TRACKED_EVENT_COUNT, /* count marker */
};
@@ -124,6 +132,24 @@ struct xe_pmu {
* @sleep_last: Last time GT parked for RC6 estimation.
*/
ktime_t sleep_last[XE_PMU_MAX_GT];
+ /**
+ * @timer: Timer for internal Xe PMU sampling.
+ */
+ struct hrtimer timer;
+ /**
+ * @timer_last:
+ *
+ * Timestmap of the previous timer invocation.
+ */
+ ktime_t timer_last;
+ /**
+ * @timer_enabled: Should the internal sampling timer be running.
+ */
+ bool timer_enabled;
+ /**
+ * @active_gts: GT active mask.
+ */
+ unsigned int active_gts;
};
#endif
--
2.38.1
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