[Intel-gfx] [PATCH v5 4/4] drm/i915: expose EU topology through sysfs

Lionel Landwerlin lionel.g.landwerlin at intel.com
Wed Nov 22 13:10:59 UTC 2017


With the introduction of asymetric slices in CNL, we cannot rely on
the previous SUBSLICE_MASK getparam. Here we introduce a more detailed
way of querying the Gen's GPU topology that doesn't aggregate numbers.

This is essential for monitoring parts of the GPU with the OA unit,
because signals need to be accounted properly based on whether part of
the GPU has been fused off. The current aggregated numbers like
EU_TOTAL do not gives us sufficient information.

Here is the sysfs layout on a Skylake GT4 :

/sys/devices/pci0000:00/0000:00:02.0/drm/card0/gt/engines/rcs/topology/
├── max_eus_per_subslice
├── max_slices
├── max_subslices_per_slice
├── slice0
│   ├── subslice0
│   │   └── eus_enabled_mask
│   ├── subslice1
│   │   └── eus_enabled_mask
│   ├── subslice2
│   │   └── eus_enabled_mask
│   ├── subslice3
│   │   └── eus_enabled_mask
│   └── subslices_enabled_mask
├── slice1
│   ├── subslice0
│   │   └── eus_enabled_mask
│   ├── subslice1
│   │   └── eus_enabled_mask
│   ├── subslice2
│   │   └── eus_enabled_mask
│   ├── subslice3
│   │   └── eus_enabled_mask
│   └── subslices_enabled_mask
├── slice2
│   ├── subslice0
│   │   └── eus_enabled_mask
│   ├── subslice1
│   │   └── eus_enabled_mask
│   ├── subslice2
│   │   └── eus_enabled_mask
│   ├── subslice3
│   │   └── eus_enabled_mask
│   └── subslices_enabled_mask
└── slices_enabled_mask

Each enabled_mask file gives us a mask of the enabled units :

$ cat /sys/devices/pci0000\:00/0000\:00\:02.0/drm/card0/gt/engines/rcs/topology/slices_enabled_mask
0x7

$ cat /sys/devices/pci0000\:00/0000\:00\:02.0/drm/card0/gt/engines/rcs/topology/slice2/subslice1/eus_enabled_mask
0xff

v2: Move topology below rcs engine (Chris)
    Add max_eus_per_subslice/max_slices/max_subslices_per_slice (Lionel)

v3: Rename enabled_mask (Lionel)

v4: Move slices to drm/card/gt/rcs/topology (Tvrtko)

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h   |  27 +++++
 drivers/gpu/drm/i915/i915_sysfs.c | 208 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 235 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a4003bfc1a8f..83e6e644fd1c 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2259,6 +2259,24 @@ struct intel_cdclk_state {
 	u8 voltage_level;
 };
 
+struct intel_topology_kobject {
+	struct kobject kobj;
+	struct drm_i915_private *dev_priv;
+};
+
+struct intel_slice_kobject {
+	struct kobject kobj;
+	struct drm_i915_private *dev_priv;
+	u8 slice_index;
+};
+
+struct intel_subslice_kobject {
+	struct kobject kobj;
+	struct drm_i915_private *dev_priv;
+	u8 slice_index;
+	u8 subslice_index;
+};
+
 struct drm_i915_private {
 	struct drm_device drm;
 
@@ -2734,6 +2752,15 @@ struct drm_i915_private {
 		struct kobject gt_kobj;
 		struct kobject engines_kobj;
 		struct kobject engines_classes_kobjs[MAX_ENGINE_CLASS + 1];
+		struct kobject topology_kobj;
+
+		struct sysfs_slice {
+			struct intel_slice_kobject kobj;
+
+			struct sysfs_subslice {
+				struct intel_subslice_kobject kobj;
+			} subslices[GEN_MAX_SUBSLICES];
+		} slices[GEN_MAX_SLICES];
 	} gt_topology;
 
 	/* Abstract the submission mechanism (legacy ringbuffer or execlists) away */
diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
index d9e188813947..f31cc6f1fbb2 100644
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -559,6 +559,205 @@ static void i915_setup_error_capture(struct device *kdev) {}
 static void i915_teardown_error_capture(struct device *kdev) {}
 #endif
 
+static struct attribute slices_enabled_mask_attr = {
+	.name = "slices_enabled_mask",
+	.mode = 0444,
+};
+
+static struct attribute subslices_enabled_mask_attr = {
+	.name = "subslices_enabled_mask",
+	.mode = 0444,
+};
+
+static struct attribute eus_enabled_mask_attr = {
+	.name = "eus_enabled_mask",
+	.mode = 0444,
+};
+
+static struct attribute max_slices_attr = {
+	.name = "max_slices",
+	.mode = 0444,
+};
+
+static struct attribute max_subslices_per_slice_attr = {
+	.name = "max_subslices_per_slice",
+	.mode = 0444,
+};
+
+static struct attribute max_eus_per_subslice_attr = {
+	.name = "max_eus_per_subslice",
+	.mode = 0444,
+};
+
+static ssize_t
+show_topology_attr(struct kobject *kobj, struct attribute *attr, char *buf)
+{
+	struct drm_i915_private *dev_priv =
+		container_of(kobj, struct drm_i915_private, gt_topology.topology_kobj);
+	const struct sseu_dev_info *sseu = &INTEL_INFO(dev_priv)->sseu;
+
+	if (attr == &slices_enabled_mask_attr)
+		return sprintf(buf, "0x%hhx\n", sseu->slice_mask);
+	if (attr == &max_eus_per_subslice_attr)
+		return sprintf(buf, "%hhd\n", sseu->max_eus_per_subslice);
+	if (attr == &max_subslices_per_slice_attr)
+		return sprintf(buf, "%hhd\n", sseu->max_subslices);
+	if (attr == &max_slices_attr)
+		return sprintf(buf, "%hhd\n", sseu->max_slices);
+	return sprintf(buf, "\n");
+}
+
+static const struct sysfs_ops topology_ops = {
+	.show = show_topology_attr,
+};
+
+static struct kobj_type topology_type = {
+	.sysfs_ops = &topology_ops,
+};
+
+static ssize_t
+show_slice_attr(struct kobject *kobj, struct attribute *attr, char *buf)
+{
+	struct intel_slice_kobject *kobj_wrapper =
+		container_of(kobj, struct intel_slice_kobject, kobj);
+	struct drm_i915_private *dev_priv = kobj_wrapper->dev_priv;
+	const struct sseu_dev_info *sseu = &INTEL_INFO(dev_priv)->sseu;
+
+	if (attr == &subslices_enabled_mask_attr) {
+		return sprintf(buf, "0x%hhx\n",
+			       sseu->subslices_mask[kobj_wrapper->slice_index]);
+	}
+	return sprintf(buf, "\n");
+}
+
+static const struct sysfs_ops slice_ops = {
+	.show = show_slice_attr,
+};
+
+static struct kobj_type slice_type = {
+	.sysfs_ops = &slice_ops,
+};
+
+static ssize_t
+show_subslice_attr(struct kobject *kobj, struct attribute *attr, char *buf)
+{
+	struct intel_subslice_kobject *kobj_wrapper =
+		container_of(kobj, struct intel_subslice_kobject, kobj);
+	struct drm_i915_private *dev_priv = kobj_wrapper->dev_priv;
+	const struct sseu_dev_info *sseu = &INTEL_INFO(dev_priv)->sseu;
+	int subslice_stride = ALIGN(sseu->max_eus_per_subslice, 8) / 8;
+	int slice_stride = sseu->max_subslices * subslice_stride;
+
+	if (attr == &eus_enabled_mask_attr)
+		return sprintf(buf, "0x%hhx\n",
+			       sseu->eu_mask[kobj_wrapper->slice_index * slice_stride +
+					     kobj_wrapper->subslice_index * subslice_stride]);
+	return sprintf(buf, "\n");
+}
+
+static const struct sysfs_ops subslice_ops = {
+	.show = show_subslice_attr,
+};
+
+static struct kobj_type subslice_type = {
+	.sysfs_ops = &subslice_ops,
+};
+
+static int i915_setup_rcs_topology_sysfs(struct drm_i915_private *dev_priv,
+					 struct kobject *engine_class_kobj)
+{
+	const struct sseu_dev_info *sseu = &INTEL_INFO(dev_priv)->sseu;
+	struct kobject *topology_kobj = &dev_priv->gt_topology.topology_kobj;
+	int ret, s, ss;
+
+	ret = kobject_init_and_add(topology_kobj, &topology_type,
+				   engine_class_kobj, "topology");
+	if (ret)
+		return ret;
+
+	ret = sysfs_create_file(topology_kobj, &slices_enabled_mask_attr);
+	if (ret)
+		return ret;
+
+	ret = sysfs_create_file(topology_kobj, &max_slices_attr);
+	if (ret)
+		return ret;
+
+	ret = sysfs_create_file(topology_kobj, &max_subslices_per_slice_attr);
+	if (ret)
+		return ret;
+
+	ret = sysfs_create_file(topology_kobj, &max_eus_per_subslice_attr);
+	if (ret)
+		return ret;
+
+	for (s = 0; s < sseu->max_slices; s++) {
+		struct intel_slice_kobject *slice_kobj =
+			&dev_priv->gt_topology.slices[s].kobj;
+
+		slice_kobj->dev_priv = dev_priv;
+		slice_kobj->slice_index = s;
+		ret = kobject_init_and_add(&slice_kobj->kobj, &slice_type,
+					   topology_kobj, "slice%i", s);
+		if (ret)
+			return ret;
+
+		ret = sysfs_create_file(&slice_kobj->kobj,
+					&subslices_enabled_mask_attr);
+		if (ret)
+			return ret;
+
+		for (ss = 0; ss < sseu->max_subslices; ss++) {
+			struct intel_subslice_kobject *subslice_kobj =
+				&dev_priv->gt_topology.slices[s].subslices[ss].kobj;
+
+			subslice_kobj->dev_priv = dev_priv;
+			subslice_kobj->slice_index = s;
+			subslice_kobj->subslice_index = ss;
+			ret = kobject_init_and_add(&subslice_kobj->kobj,
+						   &subslice_type,
+						   &slice_kobj->kobj,
+						   "subslice%i", ss);
+			if (ret)
+				return ret;
+
+			ret = sysfs_create_file(&subslice_kobj->kobj,
+						&eus_enabled_mask_attr);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
+static void i915_teardown_rcs_topology_sysfs(struct drm_i915_private *dev_priv)
+{
+	const struct sseu_dev_info *sseu = &INTEL_INFO(dev_priv)->sseu;
+	struct kobject *topology_kobj = &dev_priv->gt_topology.topology_kobj;
+	int s, ss;
+
+	for (s = 0; s < sseu->max_slices; s++) {
+		struct intel_slice_kobject *slice_kobj =
+			&dev_priv->gt_topology.slices[s].kobj;
+
+		for (ss = 0; ss < sseu->max_subslices; ss++) {
+			struct intel_subslice_kobject *subslice_kobj =
+				&dev_priv->gt_topology.slices[s].subslices[ss].kobj;
+
+			sysfs_remove_file(&subslice_kobj->kobj,
+					  &eus_enabled_mask_attr);
+		}
+
+		sysfs_remove_file(&slice_kobj->kobj,
+				  &subslices_enabled_mask_attr);
+	}
+	sysfs_remove_file(topology_kobj, &slices_enabled_mask_attr);
+	sysfs_remove_file(topology_kobj, &max_eus_per_subslice_attr);
+	sysfs_remove_file(topology_kobj, &max_subslices_per_slice_attr);
+	sysfs_remove_file(topology_kobj, &max_slices_attr);
+}
+
 static struct attribute engine_class_attr = {
 	.name = "class",
 	.mode = 0444,
@@ -651,6 +850,13 @@ static int i915_setup_engines_sysfs(struct drm_i915_private *dev_priv,
 		if (ret)
 			return ret;
 
+		if (engine_for_class->class == RENDER_CLASS) {
+			ret = i915_setup_rcs_topology_sysfs(dev_priv,
+							    engine_class_kobj);
+			if (ret)
+				return ret;
+		}
+
 		for_each_engine(engine, dev_priv, id) {
 			if (engine->class != engine_for_class->class)
 				continue;
@@ -699,6 +905,8 @@ static void i915_teardown_engines_sysfs(struct drm_i915_private *dev_priv)
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;
 
+	i915_teardown_rcs_topology_sysfs(dev_priv);
+
 	for_each_engine(engine, dev_priv, id) {
 		sysfs_remove_file(&engine->instance_kobj, &engine_class_attr);
 		sysfs_remove_file(&engine->instance_kobj, &engine_id_attr);
-- 
2.15.0



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