Commit 953d57eb authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/gem: Limit the blitter sizes to ensure low preemption latency 



Currently we insert a arbitration point every 128MiB during a blitter
copy. At 8GiB/s, this is around 30ms. This is a little on the large side
if we need to inject a high priority work, so reduced it down to 8MiB or
roughly 1ms.

v2: Don't forget both fill/copy.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191028203012.14566-1-chris@chris-wilson.co.uk
parent 19c17b76

drivers/gpu/drm/i915/gem/i915_gem_object_blt.c

+2 −2
Original line number Diff line number Diff line
@@ -17,7 +17,7 @@ struct i915_vma *intel_emit_vma_fill_blt(struct intel_context *ce, 
					 u32 value)

{

	struct drm_i915_private *i915 = ce->vm->i915;

	const u32 block_size = S16_MAX * PAGE_SIZE;

	const u32 block_size = SZ_8M; /* ~1ms at 8GiB/s preemption delay */

	struct intel_engine_pool_node *pool;

	struct i915_vma *batch;

	u64 offset;
@@ -201,7 +201,7 @@ struct i915_vma *intel_emit_vma_copy_blt(struct intel_context *ce, 
					 struct i915_vma *dst)

{

	struct drm_i915_private *i915 = ce->vm->i915;

	const u32 block_size = S16_MAX * PAGE_SIZE;

	const u32 block_size = SZ_8M; /* ~1ms at 8GiB/s preemption delay */

	struct intel_engine_pool_node *pool;

	struct i915_vma *batch;

	u64 src_offset, dst_offset;

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