[Intel-gfx] [PATCH] drm/i915/pmu: Use PM timestamp instead of RING TIMESTAMP for reference
Umesh Nerlige Ramappa
umesh.nerlige.ramappa at intel.com
Tue Jan 11 01:55:23 UTC 2022
All timestamps returned by GuC for GuC PMU busyness are captured from
GUC PM TIMESTAMP. Since this timestamp does not tick when GuC goes idle,
kmd uses RING_TIMESTAMP to measure busyness of an engine with an active
context. In further stress testing, the MMIO read of the RING_TIMESTAMP
is seen to cause a rare hang. Resolve the issue by using gt specific
timestamp from PM which is in sync with the GuC PM timestamp.
Fixes: 77cdd054dd2c ("drm/i915/pmu: Connect engine busyness stats from GuC to pmu")
Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
---
drivers/gpu/drm/i915/gt/uc/intel_guc.h | 5 ++
.../gpu/drm/i915/gt/uc/intel_guc_submission.c | 56 ++++++++++++++-----
drivers/gpu/drm/i915/i915_reg.h | 3 +-
3 files changed, 50 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
index f9240d4baa69..3aabe164c329 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
@@ -206,6 +206,11 @@ struct intel_guc {
* context usage for overflows.
*/
struct delayed_work work;
+
+ /**
+ * @shift: Right shift value for the gpm timestamp
+ */
+ u32 shift;
} timestamp;
#ifdef CONFIG_DRM_I915_SELFTEST
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index 9989d121127d..d93e9547f5e4 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -1149,23 +1149,51 @@ static void guc_update_engine_gt_clks(struct intel_engine_cs *engine)
}
}
-static void guc_update_pm_timestamp(struct intel_guc *guc,
- struct intel_engine_cs *engine,
- ktime_t *now)
+static u32 gpm_timestamp_shift(struct intel_gt *gt)
{
- u32 gt_stamp_now, gt_stamp_hi;
+ intel_wakeref_t wakeref;
+ u32 reg, shift;
+
+ with_intel_runtime_pm(gt->uncore->rpm, wakeref)
+ reg = intel_uncore_read(gt->uncore, RPM_CONFIG0);
+
+ shift = (reg & GEN10_RPM_CONFIG0_CTC_SHIFT_PARAMETER_MASK) >>
+ GEN10_RPM_CONFIG0_CTC_SHIFT_PARAMETER_SHIFT;
+
+ return 3 - shift;
+}
+
+static u64 gpm_timestamp(struct intel_gt *gt)
+{
+ u32 lo, hi, old_hi, loop = 0;
+
+ hi = intel_uncore_read(gt->uncore, MISC_STATUS1);
+ do {
+ lo = intel_uncore_read(gt->uncore, MISC_STATUS0);
+ old_hi = hi;
+ hi = intel_uncore_read(gt->uncore, MISC_STATUS1);
+ } while (old_hi != hi && loop++ < 2);
+
+ return ((u64)hi << 32) | lo;
+}
+
+static void guc_update_pm_timestamp(struct intel_guc *guc, ktime_t *now)
+{
+ struct intel_gt *gt = guc_to_gt(guc);
+ u32 gt_stamp_lo, gt_stamp_hi;
+ u64 gpm_ts;
lockdep_assert_held(&guc->timestamp.lock);
gt_stamp_hi = upper_32_bits(guc->timestamp.gt_stamp);
- gt_stamp_now = intel_uncore_read(engine->uncore,
- RING_TIMESTAMP(engine->mmio_base));
+ gpm_ts = gpm_timestamp(gt) >> guc->timestamp.shift;
+ gt_stamp_lo = lower_32_bits(gpm_ts);
*now = ktime_get();
- if (gt_stamp_now < lower_32_bits(guc->timestamp.gt_stamp))
+ if (gt_stamp_lo < lower_32_bits(guc->timestamp.gt_stamp))
gt_stamp_hi++;
- guc->timestamp.gt_stamp = ((u64)gt_stamp_hi << 32) | gt_stamp_now;
+ guc->timestamp.gt_stamp = ((u64)gt_stamp_hi << 32) | gt_stamp_lo;
}
/*
@@ -1209,7 +1237,7 @@ static ktime_t guc_engine_busyness(struct intel_engine_cs *engine, ktime_t *now)
stats_saved = *stats;
gt_stamp_saved = guc->timestamp.gt_stamp;
guc_update_engine_gt_clks(engine);
- guc_update_pm_timestamp(guc, engine, now);
+ guc_update_pm_timestamp(guc, now);
intel_gt_pm_put_async(gt);
if (i915_reset_count(gpu_error) != reset_count) {
*stats = stats_saved;
@@ -1241,8 +1269,8 @@ static void __reset_guc_busyness_stats(struct intel_guc *guc)
spin_lock_irqsave(&guc->timestamp.lock, flags);
+ guc_update_pm_timestamp(guc, &unused);
for_each_engine(engine, gt, id) {
- guc_update_pm_timestamp(guc, engine, &unused);
guc_update_engine_gt_clks(engine);
engine->stats.guc.prev_total = 0;
}
@@ -1259,10 +1287,11 @@ static void __update_guc_busyness_stats(struct intel_guc *guc)
ktime_t unused;
spin_lock_irqsave(&guc->timestamp.lock, flags);
- for_each_engine(engine, gt, id) {
- guc_update_pm_timestamp(guc, engine, &unused);
+
+ guc_update_pm_timestamp(guc, &unused);
+ for_each_engine(engine, gt, id)
guc_update_engine_gt_clks(engine);
- }
+
spin_unlock_irqrestore(&guc->timestamp.lock, flags);
}
@@ -1784,6 +1813,7 @@ int intel_guc_submission_init(struct intel_guc *guc)
spin_lock_init(&guc->timestamp.lock);
INIT_DELAYED_WORK(&guc->timestamp.work, guc_timestamp_ping);
guc->timestamp.ping_delay = (POLL_TIME_CLKS / gt->clock_frequency + 1) * HZ;
+ guc->timestamp.shift = gpm_timestamp_shift(gt);
return 0;
}
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 61ade07068c8..70c5e7c237eb 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2435,7 +2435,8 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
#define RING_WAIT (1 << 11) /* gen3+, PRBx_CTL */
#define RING_WAIT_SEMAPHORE (1 << 10) /* gen6+ */
-#define GUCPMTIMESTAMP _MMIO(0xC3E8)
+#define MISC_STATUS0 _MMIO(0xA500)
+#define MISC_STATUS1 _MMIO(0xA504)
/* There are 16 64-bit CS General Purpose Registers per-engine on Gen8+ */
#define GEN8_RING_CS_GPR(base, n) _MMIO((base) + 0x600 + (n) * 8)
--
2.33.1
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