[PATCH V10] drm/xe/uapi: Use hint for guc to set GT frequency

Lucas De Marchi lucas.demarchi at intel.com
Thu Feb 27 06:56:46 UTC 2025


On Wed, Feb 26, 2025 at 03:22:24PM +0530, Tejas Upadhyay wrote:
>Allow user to provide a low latency hint. When set, KMD sends a hint
>to GuC which results in special handling for that process. SLPC will
>ramp the GT frequency aggressively every time it switches to this
>process.
>
>We need to enable the use of SLPC Compute strategy during init, but
>it will apply only to processes that set this bit during process
>creation.
>
>Improvement with this approach as below:
>
>Before,
>
>:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
>Platform: Intel(R) OpenCL Graphics
>  Device: Intel(R) Graphics [0xe20b]
>    Driver version  : 24.52.0 (Linux x64)
>    Compute units   : 160
>    Clock frequency : 2850 MHz
>    Kernel launch latency : 283.16 us
>
>After,
>
>:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
>Platform: Intel(R) OpenCL Graphics
>  Device: Intel(R) Graphics [0xe20b]
>    Driver version  : 24.52.0 (Linux x64)
>    Compute units   : 160
>    Clock frequency : 2850 MHz
>
>    Kernel launch latency : 63.38 us
>
>Compute PR: https://github.com/intel/compute-runtime/pull/794
>Mesa PR: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33214
>
>V10(Lucas):
>  - Remove doc from drm-uapi.rst
>v9(Vinay):
>  - remove extra line, align commit message
>v8(Vinay):
>  - Add separate example for using low latency hint
>v7(Jose):
>  - Update UMD PR
>  - applicable to all gpus
>V6:
>  - init flags, remove redundant flags check (MAuld)
>V5:
>  - Move uapi doc to documentation and GuC ABI specific change (Rodrigo)
>  - Modify logic to restrict exec queue flags (MAuld)
>V4:
>  - To make it clear, dont use exec queue word (Vinay)
>  - Correct typo in description of flag (Jose/Vinay)
>  - rename set_strategy api and replace ctx with exec queue(Vinay)
>  - Start with 0th bit to indentify user flags (Jose)
>V3:
>  - Conver user flag to kernel internal flag and use (Oak)
>  - Support query config for use to check kernel support (Jose)
>  - Dont need to take runtime pm (Vinay)
>V2:
>  - DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT 1 planned for other hint(Szymon)
>  - Add motivation to description (Lucas)
>
>Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
>Signed-off-by: Tejas Upadhyay <tejas.upadhyay at intel.com>
>---
> drivers/gpu/drm/xe/abi/guc_actions_slpc_abi.h |  3 +++
> drivers/gpu/drm/xe/xe_exec_queue.c            | 10 ++++++---
> drivers/gpu/drm/xe/xe_exec_queue_types.h      |  2 ++
> drivers/gpu/drm/xe/xe_guc_pc.c                | 16 ++++++++++++++
> drivers/gpu/drm/xe/xe_guc_submit.c            |  8 +++++++
> drivers/gpu/drm/xe/xe_query.c                 |  2 ++
> include/uapi/drm/xe_drm.h                     | 21 ++++++++++++++++++-

better now without the doc in the other file.

Acked-by: Lucas De Marchi <lucas.demarchi at intel.com>

Lucas De Marchi

> 7 files changed, 58 insertions(+), 4 deletions(-)
>
>diff --git a/drivers/gpu/drm/xe/abi/guc_actions_slpc_abi.h b/drivers/gpu/drm/xe/abi/guc_actions_slpc_abi.h
>index 85abe4f09ae2..b28c8fa061f7 100644
>--- a/drivers/gpu/drm/xe/abi/guc_actions_slpc_abi.h
>+++ b/drivers/gpu/drm/xe/abi/guc_actions_slpc_abi.h
>@@ -174,6 +174,9 @@ struct slpc_task_state_data {
> 	};
> } __packed;
>
>+#define SLPC_CTX_FREQ_REQ_IS_COMPUTE		REG_BIT(28)
>+#define SLPC_OPTIMIZED_STRATEGY_COMPUTE		REG_BIT(0)
>+
> struct slpc_shared_data_header {
> 	/* Total size in bytes of this shared buffer. */
> 	u32 size;
>diff --git a/drivers/gpu/drm/xe/xe_exec_queue.c b/drivers/gpu/drm/xe/xe_exec_queue.c
>index 23a9f519ce1c..7c5c003d3c40 100644
>--- a/drivers/gpu/drm/xe/xe_exec_queue.c
>+++ b/drivers/gpu/drm/xe/xe_exec_queue.c
>@@ -604,11 +604,12 @@ int xe_exec_queue_create_ioctl(struct drm_device *dev, void *data,
> 	struct xe_tile *tile;
> 	struct xe_exec_queue *q = NULL;
> 	u32 logical_mask;
>+	u32 flags = 0;
> 	u32 id;
> 	u32 len;
> 	int err;
>
>-	if (XE_IOCTL_DBG(xe, args->flags) ||
>+	if (XE_IOCTL_DBG(xe, args->flags & ~DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT) ||
> 	    XE_IOCTL_DBG(xe, args->reserved[0] || args->reserved[1]))
> 		return -EINVAL;
>
>@@ -625,6 +626,9 @@ int xe_exec_queue_create_ioctl(struct drm_device *dev, void *data,
> 	if (XE_IOCTL_DBG(xe, eci[0].gt_id >= xe->info.gt_count))
> 		return -EINVAL;
>
>+	if (args->flags & DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT)
>+		flags |= EXEC_QUEUE_FLAG_LOW_LATENCY;
>+
> 	if (eci[0].engine_class == DRM_XE_ENGINE_CLASS_VM_BIND) {
> 		if (XE_IOCTL_DBG(xe, args->width != 1) ||
> 		    XE_IOCTL_DBG(xe, args->num_placements != 1) ||
>@@ -633,8 +637,8 @@ int xe_exec_queue_create_ioctl(struct drm_device *dev, void *data,
>
> 		for_each_tile(tile, xe, id) {
> 			struct xe_exec_queue *new;
>-			u32 flags = EXEC_QUEUE_FLAG_VM;
>
>+			flags |= EXEC_QUEUE_FLAG_VM;
> 			if (id)
> 				flags |= EXEC_QUEUE_FLAG_BIND_ENGINE_CHILD;
>
>@@ -680,7 +684,7 @@ int xe_exec_queue_create_ioctl(struct drm_device *dev, void *data,
> 		}
>
> 		q = xe_exec_queue_create(xe, vm, logical_mask,
>-					 args->width, hwe, 0,
>+					 args->width, hwe, flags,
> 					 args->extensions);
> 		up_read(&vm->lock);
> 		xe_vm_put(vm);
>diff --git a/drivers/gpu/drm/xe/xe_exec_queue_types.h b/drivers/gpu/drm/xe/xe_exec_queue_types.h
>index 6eb7ff091534..cc1cffb5c87f 100644
>--- a/drivers/gpu/drm/xe/xe_exec_queue_types.h
>+++ b/drivers/gpu/drm/xe/xe_exec_queue_types.h
>@@ -85,6 +85,8 @@ struct xe_exec_queue {
> #define EXEC_QUEUE_FLAG_BIND_ENGINE_CHILD	BIT(3)
> /* kernel exec_queue only, set priority to highest level */
> #define EXEC_QUEUE_FLAG_HIGH_PRIORITY		BIT(4)
>+/* flag to indicate low latency hint to guc */
>+#define EXEC_QUEUE_FLAG_LOW_LATENCY		BIT(5)
>
> 	/**
> 	 * @flags: flags for this exec queue, should statically setup aside from ban
>diff --git a/drivers/gpu/drm/xe/xe_guc_pc.c b/drivers/gpu/drm/xe/xe_guc_pc.c
>index 02409eedb914..25040efa043f 100644
>--- a/drivers/gpu/drm/xe/xe_guc_pc.c
>+++ b/drivers/gpu/drm/xe/xe_guc_pc.c
>@@ -995,6 +995,17 @@ static int pc_init_freqs(struct xe_guc_pc *pc)
> 	return ret;
> }
>
>+static int pc_action_set_strategy(struct xe_guc_pc *pc, u32 val)
>+{
>+	int ret = 0;
>+
>+	ret = pc_action_set_param(pc,
>+				  SLPC_PARAM_STRATEGIES,
>+				  val);
>+
>+	return ret;
>+}
>+
> /**
>  * xe_guc_pc_start - Start GuC's Power Conservation component
>  * @pc: Xe_GuC_PC instance
>@@ -1054,6 +1065,11 @@ int xe_guc_pc_start(struct xe_guc_pc *pc)
> 	}
>
> 	ret = pc_action_setup_gucrc(pc, GUCRC_FIRMWARE_CONTROL);
>+	if (ret)
>+		goto out;
>+
>+	/* Enable SLPC Optimized Strategy for compute */
>+	ret = pc_action_set_strategy(pc, SLPC_OPTIMIZED_STRATEGY_COMPUTE);
>
> out:
> 	xe_force_wake_put(gt_to_fw(gt), fw_ref);
>diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
>index b6a2dd742ebd..b95934055f72 100644
>--- a/drivers/gpu/drm/xe/xe_guc_submit.c
>+++ b/drivers/gpu/drm/xe/xe_guc_submit.c
>@@ -15,6 +15,7 @@
> #include <drm/drm_managed.h>
>
> #include "abi/guc_actions_abi.h"
>+#include "abi/guc_actions_slpc_abi.h"
> #include "abi/guc_klvs_abi.h"
> #include "regs/xe_lrc_layout.h"
> #include "xe_assert.h"
>@@ -400,6 +401,7 @@ static void __guc_exec_queue_policy_add_##func(struct exec_queue_policy *policy,
> MAKE_EXEC_QUEUE_POLICY_ADD(execution_quantum, EXECUTION_QUANTUM)
> MAKE_EXEC_QUEUE_POLICY_ADD(preemption_timeout, PREEMPTION_TIMEOUT)
> MAKE_EXEC_QUEUE_POLICY_ADD(priority, SCHEDULING_PRIORITY)
>+MAKE_EXEC_QUEUE_POLICY_ADD(slpc_exec_queue_freq_req, SLPM_GT_FREQUENCY)
> #undef MAKE_EXEC_QUEUE_POLICY_ADD
>
> static const int xe_exec_queue_prio_to_guc[] = {
>@@ -414,14 +416,20 @@ static void init_policies(struct xe_guc *guc, struct xe_exec_queue *q)
> 	struct exec_queue_policy policy;
> 	enum xe_exec_queue_priority prio = q->sched_props.priority;
> 	u32 timeslice_us = q->sched_props.timeslice_us;
>+	u32 slpc_exec_queue_freq_req = 0;
> 	u32 preempt_timeout_us = q->sched_props.preempt_timeout_us;
>
> 	xe_gt_assert(guc_to_gt(guc), exec_queue_registered(q));
>
>+	if (q->flags & EXEC_QUEUE_FLAG_LOW_LATENCY)
>+		slpc_exec_queue_freq_req |= SLPC_CTX_FREQ_REQ_IS_COMPUTE;
>+
> 	__guc_exec_queue_policy_start_klv(&policy, q->guc->id);
> 	__guc_exec_queue_policy_add_priority(&policy, xe_exec_queue_prio_to_guc[prio]);
> 	__guc_exec_queue_policy_add_execution_quantum(&policy, timeslice_us);
> 	__guc_exec_queue_policy_add_preemption_timeout(&policy, preempt_timeout_us);
>+	__guc_exec_queue_policy_add_slpc_exec_queue_freq_req(&policy,
>+							     slpc_exec_queue_freq_req);
>
> 	xe_guc_ct_send(&guc->ct, (u32 *)&policy.h2g,
> 		       __guc_exec_queue_policy_action_size(&policy), 0, 0);
>diff --git a/drivers/gpu/drm/xe/xe_query.c b/drivers/gpu/drm/xe/xe_query.c
>index ebfae746f861..e802bf34c02c 100644
>--- a/drivers/gpu/drm/xe/xe_query.c
>+++ b/drivers/gpu/drm/xe/xe_query.c
>@@ -339,6 +339,8 @@ static int query_config(struct xe_device *xe, struct drm_xe_device_query *query)
> 	if (xe_device_get_root_tile(xe)->mem.vram.usable_size)
> 		config->info[DRM_XE_QUERY_CONFIG_FLAGS] =
> 			DRM_XE_QUERY_CONFIG_FLAG_HAS_VRAM;
>+	config->info[DRM_XE_QUERY_CONFIG_FLAGS] |=
>+			DRM_XE_QUERY_CONFIG_FLAG_HAS_LOW_LATENCY;
> 	config->info[DRM_XE_QUERY_CONFIG_MIN_ALIGNMENT] =
> 		xe->info.vram_flags & XE_VRAM_FLAGS_NEED64K ? SZ_64K : SZ_4K;
> 	config->info[DRM_XE_QUERY_CONFIG_VA_BITS] = xe->info.va_bits;
>diff --git a/include/uapi/drm/xe_drm.h b/include/uapi/drm/xe_drm.h
>index 892f54d3aa09..6e510287eaf5 100644
>--- a/include/uapi/drm/xe_drm.h
>+++ b/include/uapi/drm/xe_drm.h
>@@ -393,6 +393,8 @@ struct drm_xe_query_mem_regions {
>  *
>  *    - %DRM_XE_QUERY_CONFIG_FLAG_HAS_VRAM - Flag is set if the device
>  *      has usable VRAM
>+ *    - %DRM_XE_QUERY_CONFIG_FLAG_HAS_LOW_LATENCY - Flag is set if the device
>+ *      has low latency hint support
>  *  - %DRM_XE_QUERY_CONFIG_MIN_ALIGNMENT - Minimal memory alignment
>  *    required by this device, typically SZ_4K or SZ_64K
>  *  - %DRM_XE_QUERY_CONFIG_VA_BITS - Maximum bits of a virtual address
>@@ -409,6 +411,7 @@ struct drm_xe_query_config {
> #define DRM_XE_QUERY_CONFIG_REV_AND_DEVICE_ID	0
> #define DRM_XE_QUERY_CONFIG_FLAGS			1
> 	#define DRM_XE_QUERY_CONFIG_FLAG_HAS_VRAM	(1 << 0)
>+	#define DRM_XE_QUERY_CONFIG_FLAG_HAS_LOW_LATENCY	(1 << 1)
> #define DRM_XE_QUERY_CONFIG_MIN_ALIGNMENT		2
> #define DRM_XE_QUERY_CONFIG_VA_BITS			3
> #define DRM_XE_QUERY_CONFIG_MAX_EXEC_QUEUE_PRIORITY	4
>@@ -1204,6 +1207,21 @@ struct drm_xe_vm_bind {
>  *     };
>  *     ioctl(fd, DRM_IOCTL_XE_EXEC_QUEUE_CREATE, &exec_queue_create);
>  *
>+ *     Allow users to provide a hint to kernel for cases demanding low latency
>+ *     profile. Please note it will have impact on power consumption. User can
>+ *     indicate low latency hint with flag while creating exec queue as
>+ *     mentioned below,
>+ *
>+ *     struct drm_xe_exec_queue_create exec_queue_create = {
>+ *          .flags = DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT,
>+ *          .extensions = 0,
>+ *          .vm_id = vm,
>+ *          .num_bb_per_exec = 1,
>+ *          .num_eng_per_bb = 1,
>+ *          .instances = to_user_pointer(&instance),
>+ *     };
>+ *     ioctl(fd, DRM_IOCTL_XE_EXEC_QUEUE_CREATE, &exec_queue_create);
>+ *
>  */
> struct drm_xe_exec_queue_create {
> #define DRM_XE_EXEC_QUEUE_EXTENSION_SET_PROPERTY		0
>@@ -1222,7 +1240,8 @@ struct drm_xe_exec_queue_create {
> 	/** @vm_id: VM to use for this exec queue */
> 	__u32 vm_id;
>
>-	/** @flags: MBZ */
>+#define DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT	(1 << 0)
>+	/** @flags: flags to use for this exec queue */
> 	__u32 flags;
>
> 	/** @exec_queue_id: Returned exec queue ID */
>-- 
>2.34.1
>


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