[Intel-gfx] [PATCH v4 2/2] drm/i915/perf: fix ctx_id read with GuC & ICL
Lionel Landwerlin
lionel.g.landwerlin at intel.com
Sat Jun 2 11:29:46 UTC 2018
One thing we didn't really understand about the OA report is that the
ContextID field (dword 2) is copy of the context descriptor (dword 1).
On Gen8->10 and without using GuC we didn't notice the issue because
we only checked the 21bits of the ContextID field in the OA reports
which matches exactly the hw_id stored into the context descriptor.
When using GuC submission we have an issue of a non matching hw_id
because GuC uses bit 20 of the hw_id to signal proxy submission. This
change introduces a mask to compare only the relevant bits.
On ICL the context descriptor format has changed and we failed to
address this. On top of using a mask we also need to shift the bits
properly.
v2: Reuse lrc_desc rather than recomputing part of it (Chris/Michel)
v3: Always pin the context we're filtering with (Chris)
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Fixes: 1de401c08fa805 ("drm/i915/perf: enable perf support on ICL")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104252
BSpec: 1237
Testcase: igt/perf/gen8-unprivileged-single-ctx-counters
---
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/i915_perf.c | 123 +++++++++++++++++++++++--------
drivers/gpu/drm/i915/intel_lrc.c | 5 ++
3 files changed, 97 insertions(+), 32 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 0ae88b671e8d..c568160ea53c 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1951,6 +1951,7 @@ struct drm_i915_private {
struct intel_context *pinned_ctx;
u32 specific_ctx_id;
+ u32 specific_ctx_id_mask;
struct hrtimer poll_check_timer;
wait_queue_head_t poll_wq;
diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 4f0eb84b3c00..a6c8d61add0c 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -737,12 +737,7 @@ static int gen8_append_oa_reports(struct i915_perf_stream *stream,
continue;
}
- /*
- * XXX: Just keep the lower 21 bits for now since I'm not
- * entirely sure if the HW touches any of the higher bits in
- * this field
- */
- ctx_id = report32[2] & 0x1fffff;
+ ctx_id = report32[2] & dev_priv->perf.oa.specific_ctx_id_mask;
/*
* Squash whatever is in the CTX_ID field if it's marked as
@@ -1203,6 +1198,33 @@ static int i915_oa_read(struct i915_perf_stream *stream,
return dev_priv->perf.oa.ops.read(stream, buf, count, offset);
}
+static struct intel_context *oa_pin_context(struct drm_i915_private *i915,
+ struct i915_gem_context *ctx)
+{
+ struct intel_engine_cs *engine = i915->engine[RCS];
+ struct intel_context *ce;
+ int ret;
+
+ ret = i915_mutex_lock_interruptible(&i915->drm);
+ if (ret)
+ return ERR_PTR(ret);
+
+ /*
+ * As the ID is the gtt offset of the context's vma we
+ * pin the vma to ensure the ID remains fixed.
+ *
+ * NB: implied RCS engine...
+ */
+ ce = intel_context_pin(ctx, engine);
+ mutex_unlock(&i915->drm.struct_mutex);
+ if (IS_ERR(ce))
+ return ce;
+
+ i915->perf.oa.pinned_ctx = ce;
+
+ return ce;
+}
+
/**
* oa_get_render_ctx_id - determine and hold ctx hw id
* @stream: An i915-perf stream opened for OA metrics
@@ -1215,40 +1237,76 @@ static int i915_oa_read(struct i915_perf_stream *stream,
*/
static int oa_get_render_ctx_id(struct i915_perf_stream *stream)
{
- struct drm_i915_private *dev_priv = stream->dev_priv;
-
- if (HAS_LOGICAL_RING_CONTEXTS(dev_priv)) {
- dev_priv->perf.oa.specific_ctx_id = stream->ctx->hw_id;
- } else {
- struct intel_engine_cs *engine = dev_priv->engine[RCS];
- struct intel_context *ce;
- int ret;
+ struct drm_i915_private *i915 = stream->dev_priv;
+ struct intel_context *ce;
- ret = i915_mutex_lock_interruptible(&dev_priv->drm);
- if (ret)
- return ret;
+ ce = oa_pin_context(i915, stream->ctx);
+ if (IS_ERR(ce))
+ return PTR_ERR(ce);
+ switch (INTEL_GEN(i915)) {
+ case 7: {
/*
- * As the ID is the gtt offset of the context's vma we
- * pin the vma to ensure the ID remains fixed.
- *
- * NB: implied RCS engine...
+ * On Haswell we don't do any post processing of the reports
+ * and don't need to use the mask.
*/
- ce = intel_context_pin(stream->ctx, engine);
- mutex_unlock(&dev_priv->drm.struct_mutex);
- if (IS_ERR(ce))
- return PTR_ERR(ce);
+ i915->perf.oa.specific_ctx_id = i915_ggtt_offset(ce->state);
+ i915->perf.oa.specific_ctx_id_mask = 0;
+ break;
+ }
- dev_priv->perf.oa.pinned_ctx = ce;
+ case 8:
+ case 9:
+ case 10:
+ if (USES_GUC_SUBMISSION(i915)) {
+ /*
+ * When using GuC, the context descriptor we write in
+ * i915 is read by GuC and rewritten before it's
+ * actually written into the hardware. The LRCA is
+ * what is put into the context id field of the
+ * context descriptor by GuC. Because it's aligned to
+ * a page, the lower 12bits are always at 0 and
+ * dropped by GuC. They won't be part of the context
+ * ID in the OA reports, so squash those lower bits.
+ */
+ i915->perf.oa.specific_ctx_id =
+ lower_32_bits(ce->lrc_desc) >> 12;
- /*
- * Explicitly track the ID (instead of calling
- * i915_ggtt_offset() on the fly) considering the difference
- * with gen8+ and execlists
- */
- dev_priv->perf.oa.specific_ctx_id = i915_ggtt_offset(ce->state);
+ /*
+ * GuC uses the top bit to signal proxy submission, so
+ * ignore that bit.
+ */
+ i915->perf.oa.specific_ctx_id_mask =
+ (1U << (GEN8_CTX_ID_WIDTH - 1)) - 1;
+ } else {
+ i915->perf.oa.specific_ctx_id = stream->ctx->hw_id;
+ i915->perf.oa.specific_ctx_id_mask =
+ (1U << GEN8_CTX_ID_WIDTH) - 1;
+ }
+ break;
+
+ case 11: {
+ struct intel_engine_cs *engine = i915->engine[RCS];
+
+ i915->perf.oa.specific_ctx_id =
+ stream->ctx->hw_id << (GEN11_SW_CTX_ID_SHIFT - 32) |
+ engine->instance << (GEN11_ENGINE_INSTANCE_SHIFT - 32) |
+ engine->class << (GEN11_ENGINE_INSTANCE_SHIFT - 32);
+ i915->perf.oa.specific_ctx_id_mask =
+ ((1U << GEN11_SW_CTX_ID_WIDTH) - 1) << (GEN11_SW_CTX_ID_SHIFT - 32) |
+ ((1U << GEN11_ENGINE_INSTANCE_WIDTH) - 1) << (GEN11_ENGINE_INSTANCE_SHIFT - 32) |
+ ((1 << GEN11_ENGINE_CLASS_WIDTH) - 1) << (GEN11_ENGINE_CLASS_SHIFT - 32);
+ break;
+ }
+
+ default:
+ MISSING_CASE(INTEL_GEN(i915));
}
+ DRM_DEBUG_DRIVER("filtering on ctx_id=0x%x ctx_id_mask=0x%x\n",
+ i915->perf.oa.specific_ctx_id,
+ i915->perf.oa.specific_ctx_id_mask);
+
return 0;
}
@@ -1265,6 +1323,7 @@ static void oa_put_render_ctx_id(struct i915_perf_stream *stream)
struct intel_context *ce;
dev_priv->perf.oa.specific_ctx_id = INVALID_CTX_ID;
+ dev_priv->perf.oa.specific_ctx_id_mask = 0;
ce = fetch_and_zero(&dev_priv->perf.oa.pinned_ctx);
if (ce) {
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index d09d2b79552f..eb25afa9694f 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -233,6 +233,11 @@ intel_lr_context_descriptor_update(struct i915_gem_context *ctx,
/* bits 12-31 */
GEM_BUG_ON(desc & GENMASK_ULL(63, 32));
+ /*
+ * The following 32bits are copied into the OA reports (dword 2).
+ * Consider updating oa_get_render_ctx_id in i915_perf.c when changing
+ * anything below.
+ */
if (INTEL_GEN(ctx->i915) >= 11) {
GEM_BUG_ON(ctx->hw_id >= BIT(GEN11_SW_CTX_ID_WIDTH));
desc |= (u64)ctx->hw_id << GEN11_SW_CTX_ID_SHIFT;
--
2.17.1
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