Re: [PATCH v2 6/9] drm/i915: expose command stream timestamp frequency to userspace

Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxx> · Tue, 7 Nov 2017 12:07:54 +0000

On 07/11/17 11:30, Ewelina Musial wrote:
On Thu, Nov 02, 2017 at 04:29:46PM +0000, Lionel Landwerlin wrote:
We use to have this fixed per generation, but starting with CNL userspace
cannot tell just off the PCI ID. Let's make this information available. This
is particularly useful for performance monitoring where much of the
normalization work is done using those timestamps (this include pipeline
statistics in both GL & Vulkan as well as OA reports).

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxx>
---
  drivers/gpu/drm/i915/i915_debugfs.c      |  2 +
  drivers/gpu/drm/i915/i915_drv.c          |  3 +
  drivers/gpu/drm/i915/i915_drv.h          |  2 +
  drivers/gpu/drm/i915/i915_reg.h          | 21 +++++++
  drivers/gpu/drm/i915/intel_device_info.c | 99 ++++++++++++++++++++++++++++++++
  include/uapi/drm/i915_drm.h              |  6 ++
  6 files changed, 133 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 39883cd915db..0897fd616a1f 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -3246,6 +3246,8 @@ static int i915_engine_info(struct seq_file *m, void *unused)
  		   yesno(dev_priv->gt.awake));
  	seq_printf(m, "Global active requests: %d\n",
  		   dev_priv->gt.active_requests);
+	seq_printf(m, "CS timestamp frequency: %llu\n",
+		   dev_priv->info.cs_timestamp_frequency);
  
  	p = drm_seq_file_printer(m);
  	for_each_engine(engine, dev_priv, id)
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index e7e9e061073b..fdd23e79fb46 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -416,6 +416,9 @@ static int i915_getparam(struct drm_device *dev, void *data,
  		if (!value)
  			return -ENODEV;
  		break;
+	case I915_PARAM_CS_TIMESTAMP_FREQUENCY:
+		value = INTEL_INFO(dev_priv)->cs_timestamp_frequency;
+		break;
  	default:
  		DRM_DEBUG("Unknown parameter %d\n", param->param);
  		return -EINVAL;
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 6cb7cd7f9420..4e804aaeaae1 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -886,6 +886,8 @@ struct intel_device_info {
  	/* Slice/subslice/EU info */
  	struct sseu_dev_info sseu;
  
+	uint64_t cs_timestamp_frequency;
+
  	struct color_luts {
  		u16 degamma_lut_size;
  		u16 gamma_lut_size;
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index a2223f01ee2a..f392f28f2cfa 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1119,9 +1119,24 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
  
  /* RPM unit config (Gen8+) */
  #define RPM_CONFIG0	    _MMIO(0x0D00)
+#define  GEN9_RPM_CONFIG0_CRYSTAL_CLOCK_FREQ_SHIFT	3
+#define  GEN9_RPM_CONFIG0_CRYSTAL_CLOCK_FREQ_MASK	(1 << GEN9_RPM_CONFIG0_CRYSTAL_CLOCK_FREQ_SHIFT)
+#define  GEN9_RPM_CONFIG0_CRYSTAL_CLOCK_FREQ_19_2_MHZ	0
+#define  GEN9_RPM_CONFIG0_CRYSTAL_CLOCK_FREQ_24_MHZ	1
+#define  GEN10_RPM_CONFIG0_CTC_SHIFT_PARAMETER_SHIFT	1
+#define  GEN10_RPM_CONFIG0_CTC_SHIFT_PARAMETER_MASK	(0x3 << GEN10_RPM_CONFIG0_CTC_SHIFT_PARAMETER_SHIFT)
+
  #define RPM_CONFIG1	    _MMIO(0x0D04)
  #define  GEN10_GT_NOA_ENABLE  (1 << 9)
  
+/* GPM unit config (assuming Gen8+, documentation is fuzzy...) */
+#define GEN8_CTC_MODE			_MMIO(0xA26C)
+#define  GEN8_CTC_SOURCE_PARAMETER_MASK 1
+#define  GEN8_CTC_SOURCE_CRYSTAL_CLOCK	0
+#define  GEN8_CTC_SOURCE_DIVIDE_LOGIC	1
+#define  GEN8_CTC_SHIFT_PARAMETER_SHIFT	1
+#define  GEN8_CTC_SHIFT_PARAMETER_MASK	(0x3 << GEN8_CTC_SHIFT_PARAMETER_SHIFT)
+
  /* RPC unit config (Gen8+) */
  #define RPC_CONFIG	    _MMIO(0x0D08)
  
@@ -8865,6 +8880,12 @@ enum skl_power_gate {
  #define ILK_TIMESTAMP_HI	_MMIO(0x70070)
  #define IVB_TIMESTAMP_CTR	_MMIO(0x44070)
  
+#define GEN8_TIMESTAMP_OVERRIDE				_MMIO(0x44074)
+#define  GEN8_TIMESTAMP_OVERRIDE_US_COUNTER_SHIFT		0
+#define  GEN8_TIMESTAMP_OVERRIDE_US_COUNTER_MASK		0x3ff
+#define  GEN8_TIMESTAMP_OVERRIDE_US_COUNTER_DENOMINATOR_SHIFT	12
+#define  GEN8_TIMESTAMP_OVERRIDE_US_COUNTER_DENOMINATOR_MASK	(0xf << 12)
+
  #define _PIPE_FRMTMSTMP_A		0x70048
  #define PIPE_FRMTMSTMP(pipe)		\
  			_MMIO_PIPE2(pipe, _PIPE_FRMTMSTMP_A)
diff --git a/drivers/gpu/drm/i915/intel_device_info.c b/drivers/gpu/drm/i915/intel_device_info.c
index db03d179fc85..9b71a9b6d80e 100644
--- a/drivers/gpu/drm/i915/intel_device_info.c
+++ b/drivers/gpu/drm/i915/intel_device_info.c
@@ -329,6 +329,100 @@ static void broadwell_sseu_info_init(struct drm_i915_private *dev_priv)
  	sseu->has_eu_pg = 0;
  }
  
+static u64 read_timestamp_frequency_from_divide(struct drm_i915_private *dev_priv)
+{
+	u32 ts_override = I915_READ(GEN8_TIMESTAMP_OVERRIDE);
+	u64 base_freq, frac_freq;
+
+	base_freq = ((ts_override & GEN8_TIMESTAMP_OVERRIDE_US_COUNTER_MASK) >>
+		     GEN8_TIMESTAMP_OVERRIDE_US_COUNTER_SHIFT) + 1;
+	base_freq *= 1000000;
+
+	frac_freq = ((ts_override &
+		      GEN8_TIMESTAMP_OVERRIDE_US_COUNTER_DENOMINATOR_MASK) >>
+		     GEN8_TIMESTAMP_OVERRIDE_US_COUNTER_DENOMINATOR_SHIFT);
+	if (frac_freq != 0)
+		frac_freq = 1000000 / (frac_freq + 1);
+
+	return base_freq + frac_freq;
+}
+
+static u64 read_timestamp_frequency(struct drm_i915_private *dev_priv)
+{
+	if (INTEL_GEN(dev_priv) <= 4) {
+		/* PRMs say:
+		 *
+		 *     "The value in this register increments once every 16
+		 *      hclks." ("CLKCFG" register)
+		 *
+		 * Since dev_priv->rawclk_freq stores the value in kHz divided
+		 * by 4, we just need to divide it again by 4.
+		 */
+		return (dev_priv->rawclk_freq * 1000) / 4;
+	} else if (INTEL_GEN(dev_priv) <= 7) {
+		/* PRMs say:
+		 *
+		 *     "The PCU TSC counts 10ns increments; this timestamp
+		 *      reflects bits 38:3 of the TSC (i.e. 80ns granularity,
+		 *      rolling over every 1.5 hours).
+		 */
+		return 12500000;
+	} else if (INTEL_GEN(dev_priv) <= 9) {
+		u32 ctc_reg = I915_READ(GEN8_CTC_MODE);
+		u64 freq = 0;
+
+		if ((ctc_reg & GEN8_CTC_SOURCE_PARAMETER_MASK) == GEN8_CTC_SOURCE_DIVIDE_LOGIC)
+			freq = read_timestamp_frequency_from_divide(dev_priv);
+		else
+			freq = IS_GEN9_LP(dev_priv) ? 19200000 : 24000000;
What means those values? It looks like some 'magic numbers' here.
Some comment or define could be helpful.

That's 19.2MHz or 24MHz.
Thanks, will add.

+
+		/* Now figure out how the command stream's timestamp register
+		 * increments from this frequency (it might increment only
+		 * every few clock cycle).
+		 */
+		freq >>= 3 - ((ctc_reg & GEN8_CTC_SHIFT_PARAMETER_MASK) >>
+			      GEN8_CTC_SHIFT_PARAMETER_SHIFT);
+
+		return freq;
+	} else if (INTEL_GEN(dev_priv) <= 10) {
+		u32 ctc_reg = I915_READ(GEN8_CTC_MODE);
+		u64 freq = 0;
+		u32 rpm_config_reg = 0;
+
+		/* First figure out the reference frequency. There are 2 ways
+		 * we can compute the frequency, either through the
+		 * TIMESTAMP_OVERRIDE register or through CTC_MODE &
+		 * RPM_CONFIG & CTC_MODE registers. CTC_MODE tells us which
+		 * one we should use.
+		 */
+		if ((ctc_reg & GEN8_CTC_SOURCE_PARAMETER_MASK) == GEN8_CTC_SOURCE_DIVIDE_LOGIC) {
+			freq = read_timestamp_frequency_from_divide(dev_priv);
+		} else {
+			u32 crystal_clock;
+
+			rpm_config_reg = I915_READ(RPM_CONFIG0);
+			crystal_clock = (rpm_config_reg &
+					 GEN9_RPM_CONFIG0_CRYSTAL_CLOCK_FREQ_MASK) >>
+				GEN9_RPM_CONFIG0_CRYSTAL_CLOCK_FREQ_SHIFT;
+			freq = crystal_clock == GEN9_RPM_CONFIG0_CRYSTAL_CLOCK_FREQ_19_2_MHZ ?
+				19200000 : 24000000;
The same here.
- Ewelina
+		}
+
+		/* Now figure out how the command stream's timestamp register
+		 * increments from this frequency (it might increment only
+		 * every few clock cycle).
+		 */
+		freq >>= 3 - ((rpm_config_reg &
+			       GEN10_RPM_CONFIG0_CTC_SHIFT_PARAMETER_MASK) >>
+			      GEN10_RPM_CONFIG0_CTC_SHIFT_PARAMETER_SHIFT);
+
+		return freq;
+	}
+
+	DRM_ERROR("Unknown gen, unable to compute command stream timestamp frequency\n");
+	return 0;
+}
+
  /*
   * Determine various intel_device_info fields at runtime.
   *
@@ -450,6 +544,9 @@ void intel_device_info_runtime_init(struct drm_i915_private *dev_priv)
  	else if (INTEL_GEN(dev_priv) >= 10)
  		gen10_sseu_info_init(dev_priv);
  
+	/* Initialize command stream timestamp frequency */
+	info->cs_timestamp_frequency = read_timestamp_frequency(dev_priv);
+
  	DRM_DEBUG_DRIVER("slice mask: %04x\n", info->sseu.slice_mask);
  	DRM_DEBUG_DRIVER("slice total: %u\n", hweight8(info->sseu.slice_mask));
  	DRM_DEBUG_DRIVER("subslice total: %u\n",
@@ -465,4 +562,6 @@ void intel_device_info_runtime_init(struct drm_i915_private *dev_priv)
  			 info->sseu.has_subslice_pg ? "y" : "n");
  	DRM_DEBUG_DRIVER("has EU power gating: %s\n",
  			 info->sseu.has_eu_pg ? "y" : "n");
+	DRM_DEBUG_DRIVER("CS timestamp frequency: %llu\n",
+			 info->cs_timestamp_frequency);
  }
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 125bde7d9504..c3ff0d4947af 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -450,6 +450,12 @@ typedef struct drm_i915_irq_wait {
   */
  #define I915_PARAM_HAS_EXEC_FENCE_ARRAY  49
  
+/* Frequency of the command streamer timestamps given by the *_TIMESTAMP
+ * registers. This used to be fixed per platform but from CNL onwards, this
+ * might vary depending on the parts.
+ */
+#define I915_PARAM_CS_TIMESTAMP_FREQUENCY   50
+
  typedef struct drm_i915_getparam {
  	__s32 param;
  	/*
--
2.15.0

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