[Intel-xe] [PATCH 4/4] drm/xe: Add DRM_XE_PREEMPT_TIMEOUT_COPY

[Niranjana Vishwanathapura]

Allow preemption timeout for copy engines to be specified as a
config option.

If all copy engines are thrashing away at the PCIe bus, plus all
compute engines doing the same, then the per copy bandwidth becomes
tiny. That results in copy operations that should take milliseconds
actually taking seconds. So bump the pre-emption timeout to allow for
the worst case scenario (currently believed to be around 2s).

Signed-off-by: John Harrison <John.C.Harrison at Intel.com>
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura at intel.com>
---
 drivers/gpu/drm/xe/Kconfig.profile | 12 ++++++++++++
 drivers/gpu/drm/xe/xe_hw_engine.c  |  4 ++++
 drivers/gpu/drm/xe/xe_hw_engine.h  |  6 ++++++
 3 files changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/xe/Kconfig.profile b/drivers/gpu/drm/xe/Kconfig.profile
index 5ca3305a22b6..219e13d3fd25 100644
--- a/drivers/gpu/drm/xe/Kconfig.profile
+++ b/drivers/gpu/drm/xe/Kconfig.profile
@@ -43,6 +43,18 @@ config DRM_XE_PREEMPT_TIMEOUT_COMPUTE
 	  before the timer expires, the HW will be reset to allow the more
 	  important context to execute.
 
+	  Value should be within the DRM_XE_PREEMPT_TIMEOUT_MIN/MAX limits.
+	  This is adjustable via XE_ENGINE_SET_PROPERTY_PREEMPTION_TIMEOUT.
+config DRM_XE_PREEMPT_TIMEOUT_COPY
+	int "Preempt timeout for copy engines (ms, jiffy granularity)"
+	default 2500 # milliseconds
+	help
+	  How long to wait (in milliseconds) for a preemption event to occur
+	  when submitting a new context to a copy engine. If the current
+	  context does not hit an arbitration point and yield to HW before
+	  the timer expires, the HW will be reset to allow the more important
+	  context to execute.
+
 	  Value should be within the DRM_XE_PREEMPT_TIMEOUT_MIN/MAX limits.
 	  This is adjustable via XE_ENGINE_SET_PROPERTY_PREEMPTION_TIMEOUT.
 config DRM_XE_PREEMPT_TIMEOUT_MAX
diff --git a/drivers/gpu/drm/xe/xe_hw_engine.c b/drivers/gpu/drm/xe/xe_hw_engine.c
index 57a0fb50852c..34b1fdd24b0e 100644
--- a/drivers/gpu/drm/xe/xe_hw_engine.c
+++ b/drivers/gpu/drm/xe/xe_hw_engine.c
@@ -343,6 +343,8 @@ static u32 get_default_preempt_timeout(struct xe_hw_engine *hwe)
 	if (hwe->class == XE_ENGINE_CLASS_RENDER ||
 	    hwe->class == XE_ENGINE_CLASS_COMPUTE)
 		return XE_HW_ENGINE_PREEMPT_TIMEOUT_COMPUTE;
+	else if (hwe->class == XE_ENGINE_CLASS_COPY)
+		return XE_HW_ENGINE_PREEMPT_TIMEOUT_COPY;
 	else
 		return XE_HW_ENGINE_PREEMPT_TIMEOUT;
 }
@@ -575,6 +577,8 @@ int xe_hw_engines_init_early(struct xe_gt *gt)
 	BUILD_BUG_ON(XE_HW_ENGINE_PREEMPT_TIMEOUT > XE_HW_ENGINE_PREEMPT_TIMEOUT_MAX);
 	BUILD_BUG_ON(XE_HW_ENGINE_PREEMPT_TIMEOUT_COMPUTE < XE_HW_ENGINE_PREEMPT_TIMEOUT_MIN);
 	BUILD_BUG_ON(XE_HW_ENGINE_PREEMPT_TIMEOUT_COMPUTE > XE_HW_ENGINE_PREEMPT_TIMEOUT_MAX);
+	BUILD_BUG_ON(XE_HW_ENGINE_PREEMPT_TIMEOUT_COPY < XE_HW_ENGINE_PREEMPT_TIMEOUT_MIN);
+	BUILD_BUG_ON(XE_HW_ENGINE_PREEMPT_TIMEOUT_COPY > XE_HW_ENGINE_PREEMPT_TIMEOUT_MAX);
 
 	for (i = 0; i < ARRAY_SIZE(gt->hw_engines); i++)
 		hw_engine_init_early(gt, &gt->hw_engines[i], i);
diff --git a/drivers/gpu/drm/xe/xe_hw_engine.h b/drivers/gpu/drm/xe/xe_hw_engine.h
index c4f0969efc06..66a611f4942a 100644
--- a/drivers/gpu/drm/xe/xe_hw_engine.h
+++ b/drivers/gpu/drm/xe/xe_hw_engine.h
@@ -41,6 +41,12 @@ struct drm_printer;
 #else
 #define XE_HW_ENGINE_PREEMPT_TIMEOUT_COMPUTE XE_HW_ENGINE_PREEMPT_TIMEOUT
 #endif
+#ifdef CONFIG_DRM_XE_PREEMPT_TIMEOUT_COPY
+#define XE_HW_ENGINE_PREEMPT_TIMEOUT_COPY \
+	(CONFIG_DRM_XE_PREEMPT_TIMEOUT_COPY * 1000)
+#else
+#define XE_HW_ENGINE_PREEMPT_TIMEOUT_COPY XE_HW_ENGINE_PREEMPT_TIMEOUT
+#endif
 #ifdef CONFIG_DRM_XE_PREEMPT_TIMEOUT_MIN
 #define XE_HW_ENGINE_PREEMPT_TIMEOUT_MIN CONFIG_DRM_XE_PREEMPT_TIMEOUT_MIN
 #else
-- 
2.21.0.rc0.32.g243a4c7e27