[Intel-gfx] [PATCH] drm/i915/perf: introduce global sseu pinning

* [Intel-gfx] [PATCH] drm/i915/perf: introduce global sseu pinning
@ 2020-02-28 16:02 Lionel Landwerlin
  2020-02-28 16:44 ` Chris Wilson
  2020-02-28 18:13 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for " Patchwork
  0 siblings, 2 replies; 4+ messages in thread
From: Lionel Landwerlin @ 2020-02-28 16:02 UTC (permalink / raw)
  To: intel-gfx

On Gen11 powergating half the execution units is a functional
requirement when using the VME samplers. Not fullfilling this
requirement can lead to hangs.

This unfortunately plays fairly poorly with the NOA requirements. NOA
requires a stable power configuration to maintain its configuration.

As a result using OA (and NOA feeding into it) so far has required us
to use a power configuration that can work for all contexts. The only
power configuration fullfilling this is powergating half the execution
units.

This makes performance analysis for 3D workloads somewhat pointless.

Failing to find a solution that would work for everybody, this change
introduces a new i915-perf stream open parameter that punts the
decision off to userspace. If this parameter is omitted, the existing
Gen11 behavior remains (half EU array powergating).

This change takes the initiative to move all perf related sseu
configuration into i915_perf.c

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c | 10 +--
 drivers/gpu/drm/i915/gem/i915_gem_context.h |  4 +
 drivers/gpu/drm/i915/gt/intel_sseu.c        | 34 +-------
 drivers/gpu/drm/i915/i915_perf.c            | 90 ++++++++++++++++++---
 drivers/gpu/drm/i915/i915_perf_types.h      |  7 ++
 include/uapi/drm/i915_drm.h                 | 11 +++
 6 files changed, 108 insertions(+), 48 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index e525ead073f7..652f84c3cc2b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -1279,10 +1279,10 @@ static int get_ringsize(struct i915_gem_context *ctx,
 	return 0;
 }
 
-static int
-user_to_context_sseu(struct drm_i915_private *i915,
-		     const struct drm_i915_gem_context_param_sseu *user,
-		     struct intel_sseu *context)
+int
+i915_gem_user_to_context_sseu(struct drm_i915_private *i915,
+			      const struct drm_i915_gem_context_param_sseu *user,
+			      struct intel_sseu *context)
 {
 	const struct sseu_dev_info *device = &RUNTIME_INFO(i915)->sseu;
 
@@ -1417,7 +1417,7 @@ static int set_sseu(struct i915_gem_context *ctx,
 		goto out_ce;
 	}
 
-	ret = user_to_context_sseu(i915, &user_sseu, &sseu);
+	ret = i915_gem_user_to_context_sseu(i915, &user_sseu, &sseu);
 	if (ret)
 		goto out_ce;
 
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.h b/drivers/gpu/drm/i915/gem/i915_gem_context.h
index 3ae61a355d87..dff1380373f4 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.h
@@ -222,4 +222,8 @@ i915_gem_engines_iter_next(struct i915_gem_engines_iter *it);
 struct i915_lut_handle *i915_lut_handle_alloc(void);
 void i915_lut_handle_free(struct i915_lut_handle *lut);
 
+int i915_gem_user_to_context_sseu(struct drm_i915_private *i915,
+				  const struct drm_i915_gem_context_param_sseu *user,
+				  struct intel_sseu *context);
+
 #endif /* !__I915_GEM_CONTEXT_H__ */
diff --git a/drivers/gpu/drm/i915/gt/intel_sseu.c b/drivers/gpu/drm/i915/gt/intel_sseu.c
index 74f793423231..b01b6e2c3e54 100644
--- a/drivers/gpu/drm/i915/gt/intel_sseu.c
+++ b/drivers/gpu/drm/i915/gt/intel_sseu.c
@@ -65,7 +65,6 @@ u32 intel_sseu_make_rpcs(struct drm_i915_private *i915,
 {
 	const struct sseu_dev_info *sseu = &RUNTIME_INFO(i915)->sseu;
 	bool subslice_pg = sseu->has_subslice_pg;
-	struct intel_sseu ctx_sseu;
 	u8 slices, subslices;
 	u32 rpcs = 0;
 
@@ -76,33 +75,8 @@ u32 intel_sseu_make_rpcs(struct drm_i915_private *i915,
 	if (INTEL_GEN(i915) < 9)
 		return 0;
 
-	/*
-	 * If i915/perf is active, we want a stable powergating configuration
-	 * on the system.
-	 *
-	 * We could choose full enablement, but on ICL we know there are use
-	 * cases which disable slices for functional, apart for performance
-	 * reasons. So in this case we select a known stable subset.
-	 */
-	if (!i915->perf.exclusive_stream) {
-		ctx_sseu = *req_sseu;
-	} else {
-		ctx_sseu = intel_sseu_from_device_info(sseu);
-
-		if (IS_GEN(i915, 11)) {
-			/*
-			 * We only need subslice count so it doesn't matter
-			 * which ones we select - just turn off low bits in the
-			 * amount of half of all available subslices per slice.
-			 */
-			ctx_sseu.subslice_mask =
-				~(~0 << (hweight8(ctx_sseu.subslice_mask) / 2));
-			ctx_sseu.slice_mask = 0x1;
-		}
-	}
-
-	slices = hweight8(ctx_sseu.slice_mask);
-	subslices = hweight8(ctx_sseu.subslice_mask);
+	slices = hweight8(req_sseu->slice_mask);
+	subslices = hweight8(req_sseu->subslice_mask);
 
 	/*
 	 * Since the SScount bitfield in GEN8_R_PWR_CLK_STATE is only three bits
@@ -175,13 +149,13 @@ u32 intel_sseu_make_rpcs(struct drm_i915_private *i915,
 	if (sseu->has_eu_pg) {
 		u32 val;
 
-		val = ctx_sseu.min_eus_per_subslice << GEN8_RPCS_EU_MIN_SHIFT;
+		val = req_sseu->min_eus_per_subslice << GEN8_RPCS_EU_MIN_SHIFT;
 		GEM_BUG_ON(val & ~GEN8_RPCS_EU_MIN_MASK);
 		val &= GEN8_RPCS_EU_MIN_MASK;
 
 		rpcs |= val;
 
-		val = ctx_sseu.max_eus_per_subslice << GEN8_RPCS_EU_MAX_SHIFT;
+		val = req_sseu->max_eus_per_subslice << GEN8_RPCS_EU_MAX_SHIFT;
 		GEM_BUG_ON(val & ~GEN8_RPCS_EU_MAX_MASK);
 		val &= GEN8_RPCS_EU_MAX_MASK;
 
diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 3883c21b13b2..5b4088e125f9 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -344,6 +344,8 @@ static const struct i915_oa_format gen12_oa_formats[I915_OA_FORMAT_MAX] = {
  * @oa_periodic: Whether to enable periodic OA unit sampling
  * @oa_period_exponent: The OA unit sampling period is derived from this
  * @engine: The engine (typically rcs0) being monitored by the OA unit
+ * @user_sseu_present: Whether @user_sseu was specified by the user
+ * @user_sseu: Selected sseu configuration for recording
  *
  * As read_properties_unlocked() enumerates and validates the properties given
  * to open a stream of metrics the configuration is built up in the structure
@@ -363,6 +365,9 @@ struct perf_open_properties {
 	int oa_period_exponent;
 
 	struct intel_engine_cs *engine;
+
+	bool user_sseu_present;
+	struct drm_i915_gem_context_param_sseu user_sseu;
 };
 
 struct i915_oa_config_bo {
@@ -2117,9 +2122,6 @@ gen8_update_reg_state_unlocked(const struct intel_context *ce,
 	for (i = 0; i < ARRAY_SIZE(flex_regs); i++)
 		reg_state[ctx_flexeu0 + i * 2 + 1] =
 			oa_config_flex_reg(stream->oa_config, flex_regs[i]);
-
-	reg_state[CTX_R_PWR_CLK_STATE] =
-		intel_sseu_make_rpcs(ce->engine->i915, &ce->sseu);
 }
 
 struct flex {
@@ -2213,7 +2215,8 @@ static int gen8_modify_self(struct intel_context *ce,
 	return err;
 }
 
-static int gen8_configure_context(struct i915_gem_context *ctx,
+static int gen8_configure_context(struct i915_perf_stream *stream,
+				  struct i915_gem_context *ctx,
 				  struct flex *flex, unsigned int count)
 {
 	struct i915_gem_engines_iter it;
@@ -2230,7 +2233,7 @@ static int gen8_configure_context(struct i915_gem_context *ctx,
 		if (!intel_context_pin_if_active(ce))
 			continue;
 
-		flex->value = intel_sseu_make_rpcs(ctx->i915, &ce->sseu);
+		flex->value = intel_sseu_make_rpcs(ctx->i915, &stream->sseu);
 		err = gen8_modify_context(ce, flex, count);
 
 		intel_context_unpin(ce);
@@ -2348,7 +2351,7 @@ static int oa_configure_all_contexts(struct i915_perf_stream *stream,
 
 		spin_unlock(&i915->gem.contexts.lock);
 
-		err = gen8_configure_context(ctx, regs, num_regs);
+		err = gen8_configure_context(stream, ctx, regs, num_regs);
 		if (err) {
 			i915_gem_context_put(ctx);
 			return err;
@@ -2371,7 +2374,7 @@ static int oa_configure_all_contexts(struct i915_perf_stream *stream,
 		if (engine->class != RENDER_CLASS)
 			continue;
 
-		regs[0].value = intel_sseu_make_rpcs(i915, &ce->sseu);
+		regs[0].value = intel_sseu_make_rpcs(i915, &stream->sseu);
 
 		err = gen8_modify_self(ce, regs, num_regs);
 		if (err)
@@ -2728,6 +2731,47 @@ static const struct i915_perf_stream_ops i915_oa_stream_ops = {
 	.read = i915_oa_read,
 };
 
+static int
+get_sseu_config(struct intel_sseu *out_sseu,
+		struct intel_engine_cs *engine,
+		const struct perf_open_properties *properties)
+{
+	struct intel_engine_cs *user_engine;
+
+	if (!properties->user_sseu_present) {
+		const struct sseu_dev_info *devinfo_sseu = &RUNTIME_INFO(engine->i915)->sseu;
+
+		*out_sseu = intel_sseu_from_device_info(devinfo_sseu);
+
+		if (IS_GEN(engine->i915, 11)) {
+			/*
+			 * We only need subslice count so it doesn't matter
+			 * which ones we select - just turn off low bits in the
+			 * amount of half of all available subslices per slice.
+			 */
+			out_sseu->subslice_mask =
+				~(~0 << (hweight8(out_sseu->subslice_mask) / 2));
+			out_sseu->slice_mask = 0x1;
+		}
+
+		return 0;
+	}
+
+	user_engine = intel_engine_lookup_user(
+		engine->i915,
+		properties->user_sseu.engine.engine_class,
+		properties->user_sseu.engine.engine_instance);
+	if (!user_engine)
+		return -EINVAL;
+
+	if (user_engine != engine)
+		return -EINVAL;
+
+	return i915_gem_user_to_context_sseu(engine->i915,
+					     &properties->user_sseu,
+					     out_sseu);
+}
+
 /**
  * i915_oa_stream_init - validate combined props for OA stream and init
  * @stream: An i915 perf stream
@@ -2812,6 +2856,10 @@ static int i915_oa_stream_init(struct i915_perf_stream *stream,
 
 	stream->hold_preemption = props->hold_preemption;
 
+	ret = get_sseu_config(&stream->sseu, stream->engine, props);
+	if (ret)
+		return ret;
+
 	stream->oa_buffer.format =
 		perf->oa_formats[props->oa_format].format;
 
@@ -2919,12 +2967,14 @@ void i915_oa_init_reg_state(const struct intel_context *ce,
 		return;
 
 	stream = engine->i915->perf.exclusive_stream;
-	/*
-	 * For gen12, only CTX_R_PWR_CLK_STATE needs update, but the caller
-	 * is already doing that, so nothing to be done for gen12 here.
-	 */
-	if (stream && INTEL_GEN(stream->perf->i915) < 12)
+	if (stream) {
+		u32 *reg_state = ce->lrc_reg_state;
+
 		gen8_update_reg_state_unlocked(ce, stream);
+
+		reg_state[CTX_R_PWR_CLK_STATE] =
+			intel_sseu_make_rpcs(ce->engine->i915, &stream->sseu);
+	}
 }
 
 /**
@@ -3628,6 +3678,16 @@ static int read_properties_unlocked(struct i915_perf *perf,
 		case DRM_I915_PERF_PROP_HOLD_PREEMPTION:
 			props->hold_preemption = !!value;
 			break;
+		case DRM_I915_PERF_PROP_GLOBAL_SSEU: {
+			if (copy_from_user(&props->user_sseu,
+					   u64_to_user_ptr(value),
+					   sizeof(props->user_sseu))) {
+				DRM_DEBUG("Unable to copy global sseu parameter\n");
+				return -EFAULT;
+			}
+			props->user_sseu_present = true;
+			break;
+		}
 		case DRM_I915_PERF_PROP_MAX:
 			MISSING_CASE(id);
 			return -EINVAL;
@@ -4401,8 +4461,12 @@ int i915_perf_ioctl_version(void)
 	 *    preemption on a particular context so that performance data is
 	 *    accessible from a delta of MI_RPC reports without looking at the
 	 *    OA buffer.
+	 *
+	 * 4: Add DRM_I915_PERF_PROP_ALLOWED_SSEU to limit what contexts can
+	 *    be run for the duration of the performance recording based on
+	 *    their SSEU configuration.
 	 */
-	return 3;
+	return 4;
 }
 
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
diff --git a/drivers/gpu/drm/i915/i915_perf_types.h b/drivers/gpu/drm/i915/i915_perf_types.h
index 92fd3cf5afcc..ee2688c28771 100644
--- a/drivers/gpu/drm/i915/i915_perf_types.h
+++ b/drivers/gpu/drm/i915/i915_perf_types.h
@@ -16,6 +16,7 @@
 #include <linux/uuid.h>
 #include <linux/wait.h>
 
+#include "gt/intel_sseu.h"
 #include "i915_reg.h"
 #include "intel_wakeref.h"
 
@@ -317,6 +318,12 @@ struct i915_perf_stream {
 	 * through the OA buffer to be valid.
 	 */
 	struct i915_request *configure_request;
+
+	/**
+	 * @sseu: sseu configuration selected to run while perf is active,
+	 * applies to all contexts.
+	 */
+	struct intel_sseu sseu;
 };
 
 /**
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 2813e579b480..db649d03ab52 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1969,6 +1969,17 @@ enum drm_i915_perf_property_id {
 	 */
 	DRM_I915_PERF_PROP_HOLD_PREEMPTION,
 
+	/**
+	 * Specifying this pins all contexts to the specified SSEU power
+	 * configuration for the duration of the recording.
+	 *
+	 * This parameter's value is a pointer to a struct
+	 * drm_i915_gem_context_param_sseu.
+	 *
+	 * This property is available in perf revision 4.
+	 */
+	DRM_I915_PERF_PROP_GLOBAL_SSEU,
+
 	DRM_I915_PERF_PROP_MAX /* non-ABI */
 };
 
-- 
2.25.1

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