From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
We want to allow userspace to reconfigure the subslice configuration for
its own use case. To do so, we expose a context parameter to allow
adjustment of the RPCS register stored within the context image (and
currently not accessible via LRI). If the context is adjusted before
first use, the adjustment is for "free"; otherwise if the context is
active we flush the context off the GPU (stalling all users) and forcing
the GPU to save the context to memory where we can modify it and so
ensure that the register is reloaded on next execution.
The overhead of managing additional EU subslices can be significant,
especially in multi-context workloads. Non-GPGPU contexts should
preferably disable the subslices it is not using, and others should
fine-tune the number to match their workload.
We expose complete control over the RPCS register, allowing
configuration of slice/subslice, via masks packed into a u64 for
simplicity. For example,
struct drm_i915_gem_context_param arg;
struct drm_i915_gem_context_param_sseu sseu = { .flags = I915_EXEC_RENDER };
memset(&arg, 0, sizeof(arg));
arg.ctx_id = ctx;
arg.param = I915_CONTEXT_PARAM_SSEU;
arg.value = (uintptr_t) &sseu;
if (drmIoctl(fd, DRM_IOCTL_I915_GEM_CONTEXT_GETPARAM, &arg) == 0) {
sseu.packed.subslice_mask = 0;
drmIoctl(fd, DRM_IOCTL_I915_GEM_CONTEXT_SETPARAM, &arg);
}
could be used to disable all subslices where supported.
v2: Fix offset of CTX_R_PWR_CLK_STATE in intel_lr_context_set_sseu() (Lionel)
v3: Add ability to program this per engine (Chris)
v4: Move most get_sseu() into i915_gem_context.c (Lionel)
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100899
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxx>
c: Dmitry Rogozhkin <dmitry.v.rogozhkin@xxxxxxxxx>
CC: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
CC: Zhipeng Gong <zhipeng.gong@xxxxxxxxx>
CC: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_context.c | 82 ++++++++++++++++++++++++-
drivers/gpu/drm/i915/intel_lrc.c | 55 +++++++++++++++++
drivers/gpu/drm/i915/intel_lrc.h | 4 ++
include/uapi/drm/i915_drm.h | 28 +++++++++
4 files changed, 168 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index bdf050beeb94..b97ddcf47514 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -740,6 +740,26 @@ int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data,
return 0;
}
+static struct i915_gem_context_sseu
+i915_gem_context_sseu_from_user_sseu(const struct sseu_dev_info *sseu,
+ const struct drm_i915_gem_context_param_sseu *user_sseu)
+{
+ struct i915_gem_context_sseu value = {
+ .slice_mask = user_sseu->packed.slice_mask == 0 ?
+ sseu->slice_mask :
+ (user_sseu->packed.slice_mask & sseu->slice_mask),
+ .subslice_mask = user_sseu->packed.subslice_mask == 0 ?
+ sseu->subslice_mask[0] :
+ (user_sseu->packed.subslice_mask & sseu->subslice_mask[0]),
+ .min_eus_per_subslice = min(user_sseu->packed.min_eus_per_subslice,
+ sseu->max_eus_per_subslice),
+ .max_eus_per_subslice = min(user_sseu->packed.max_eus_per_subslice,
+ sseu->max_eus_per_subslice),
+ };
+
+ return value;
+}
+
int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
struct drm_file *file)
{
@@ -777,6 +797,37 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
case I915_CONTEXT_PARAM_PRIORITY:
args->value = ctx->sched.priority;
break;
+ case I915_CONTEXT_PARAM_SSEU: {
+ struct drm_i915_gem_context_param_sseu param_sseu;
+ struct intel_engine_cs *engine;
+
+ if (copy_from_user(¶m_sseu, u64_to_user_ptr(args->value),
+ sizeof(param_sseu))) {
+ ret = -EFAULT;
+ break;
+ }
+
+ engine = i915_gem_engine_from_flags(to_i915(dev), file,
+ param_sseu.flags);
+ if (!engine) {
+ ret = -EINVAL;
+ break;
+ }
+
+ param_sseu.packed.slice_mask =
+ ctx->engine[engine->id].sseu.slice_mask;
+ param_sseu.packed.subslice_mask =
+ ctx->engine[engine->id].sseu.subslice_mask;
+ param_sseu.packed.min_eus_per_subslice =
+ ctx->engine[engine->id].sseu.min_eus_per_subslice;
+ param_sseu.packed.max_eus_per_subslice =
+ ctx->engine[engine->id].sseu.max_eus_per_subslice;
+
+ if (copy_to_user(u64_to_user_ptr(args->value), ¶m_sseu,
+ sizeof(param_sseu)))
+ ret = -EFAULT;
+ break;
+ }
default:
ret = -EINVAL;
break;
@@ -832,7 +883,6 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
else
i915_gem_context_clear_bannable(ctx);
break;
-
case I915_CONTEXT_PARAM_PRIORITY:
{
s64 priority = args->value;
@@ -851,7 +901,37 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
ctx->sched.priority = priority;
}
break;
+ case I915_CONTEXT_PARAM_SSEU:
+ if (args->size)
+ ret = -EINVAL;
+ else if (!HAS_EXECLISTS(ctx->i915))
+ ret = -ENODEV;
+ else {
+ struct drm_i915_private *dev_priv = to_i915(dev);
+ struct drm_i915_gem_context_param_sseu user_sseu;
+ struct i915_gem_context_sseu ctx_sseu;
+ struct intel_engine_cs *engine;
+
+ if (copy_from_user(&user_sseu, u64_to_user_ptr(args->value),
+ sizeof(user_sseu))) {
+ ret = -EFAULT;
+ break;
+ }
+
+ engine = i915_gem_engine_from_flags(dev_priv, file,
+ user_sseu.flags);
+ if (!engine) {
+ ret = -EINVAL;
+ break;
+ }
+
+ ctx_sseu =
+ i915_gem_context_sseu_from_user_sseu(&INTEL_INFO(dev_priv)->sseu,
+ &user_sseu);
+ ret = intel_lr_context_set_sseu(ctx, engine, &ctx_sseu);
+ }
+ break;
default:
ret = -EINVAL;
break;
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index dca17ef24de5..9caddcb1f234 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -2711,6 +2711,61 @@ void intel_lr_context_resume(struct drm_i915_private *dev_priv)
}
}
+int intel_lr_context_set_sseu(struct i915_gem_context *ctx,
+ struct intel_engine_cs *engine,
+ struct i915_gem_context_sseu *sseu)
+{
+ struct drm_i915_private *dev_priv = ctx->i915;
+ struct intel_context *ce;
+ enum intel_engine_id id;
+ int ret;
+
+ lockdep_assert_held(&dev_priv->drm.struct_mutex);
+
+ if (memcmp(sseu, &ctx->engine[engine->id].sseu, sizeof(*sseu)) == 0)
+ return 0;
+
+ /*
+ * We can only program this on render ring.
+ */
+ ce = &ctx->engine[RCS];
+
+ if (ce->pin_count) { /* Assume that the context is active! */
+ ret = i915_gem_switch_to_kernel_context(dev_priv);
+ if (ret)
+ return ret;
+
+ ret = i915_gem_wait_for_idle(dev_priv,
+ I915_WAIT_INTERRUPTIBLE |
+ I915_WAIT_LOCKED);
