On 25/01/2022 05:47, Jani Nikula wrote:
On Mon, 24 Jan 2022, Umesh Nerlige Ramappa <umesh.nerlige.ramappa@xxxxxxxxx> wrote: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@xxxxxxxxx> Reviewed-by: Alan Previn <alan.previn.teres.alexis@xxxxxxxxx> --- 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 d59bbf49d1c2..697d9d66acef 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h @@ -215,6 +215,11 @@ 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_SELFTESTdiff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c index 1331ff91c5b0..66760f5df0c1 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -1150,23 +1150,51 @@ 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; +}See intel_uncore_read64_2x32().
This was a good suggestion - since the patch was merged regardless I think a follow up cleanup is in order so we don't accumulate duplicated code.
Regards, Tvrtko
+ +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; }/*@@ -1210,7 +1238,7 @@ 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; @@ -1242,8 +1270,8 @@ 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; } @@ -1260,10 +1288,11 @@ 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); }@@ -1757,6 +1786,7 @@ 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 23b7c6930453..655517eb90ab 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -1848,7 +1848,8 @@ #define BLT_HWS_PGA_GEN7 _MMIO(0x04280) #define VEBOX_HWS_PGA_GEN7 _MMIO(0x04380)-#define GUCPMTIMESTAMP _MMIO(0xC3E8)+#define MISC_STATUS0 _MMIO(0xA500) +#define MISC_STATUS1 _MMIO(0xA504)#define GEN7_TLB_RD_ADDR _MMIO(0x4700)
