On Thu, 2025-01-09 at 17:37 +0530, Tejas Upadhyay wrote:
> Allow user to provide a low latency hint per exec queue. When set,
> KMD sends a hint to GuC which results in special handling for this
> exec queue. SLPC will ramp the GT frequency aggressively every time
> it switches to this exec queue.
>
> We need to enable the use of SLPC Compute strategy during init, but
> it will apply only to exec queues that set this bit during exec queue
> 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
>
> UMD will indicate low latency hint with flag as mentioned below,
>
> * struct drm_xe_exec_queue_create exec_queue_create = {
> * .flags = DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT or 0
> * .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);
>
> Link to UMD PR : https://github.com/intel/compute-runtime/pull/794
>
> Note: There is outstanding issue on guc side to be not able to switch to max
> frequency as per strategy indicated by KMD, so for experminet/test result
> hardcoding apporch was taken and passed to guc as policy. Effort on debugging
> from guc side is going on in parallel.
>
> V2:
> - DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT 1 is already planned for other hint(Szymon)
> - Add motivation to description (Lucas)
>
> Cc:dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Cc:vinay.belgaumkar@xxxxxxxxx
> Cc:Michal Mrozek <michal.mrozek@xxxxxxxxx>
> Cc:Szymon Morek <szymon.morek@xxxxxxxxx>
> Cc:José Roberto de Souza <jose.souza@xxxxxxxxx>
> Signed-off-by: Tejas Upadhyay <tejas.upadhyay@xxxxxxxxx>
> ---
> drivers/gpu/drm/xe/abi/guc_actions_slpc_abi.h | 3 +++
> drivers/gpu/drm/xe/xe_exec_queue.c | 7 ++++---
> drivers/gpu/drm/xe/xe_guc_pc.c | 16 ++++++++++++++++
> drivers/gpu/drm/xe/xe_guc_submit.c | 7 +++++++
> include/uapi/drm/xe_drm.h | 3 ++-
> 5 files changed, 32 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..c50075b8270f 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_EXEC_QUEUE_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 8948f50ee58f..7747ba6c4bb8 100644
> --- a/drivers/gpu/drm/xe/xe_exec_queue.c
> +++ b/drivers/gpu/drm/xe/xe_exec_queue.c
> @@ -553,7 +553,8 @@ int xe_exec_queue_create_ioctl(struct drm_device *dev, void *data,
> u32 len;
> int err;
>
> - if (XE_IOCTL_DBG(xe, args->flags) ||
> + if (XE_IOCTL_DBG(xe, args->flags &&
> + !(args->flags & DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT)) ||
> XE_IOCTL_DBG(xe, args->reserved[0] || args->reserved[1]))
> return -EINVAL;
>
> @@ -578,7 +579,7 @@ 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;
> + u32 flags = args->flags | EXEC_QUEUE_FLAG_VM;
>
> if (id)
> flags |= EXEC_QUEUE_FLAG_BIND_ENGINE_CHILD;
> @@ -626,7 +627,7 @@ 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, args->flags,
> args->extensions);
> up_read(&vm->lock);
> xe_vm_put(vm);
> diff --git a/drivers/gpu/drm/xe/xe_guc_pc.c b/drivers/gpu/drm/xe/xe_guc_pc.c
> index df7f130fb663..ff0b98ccf1a7 100644
> --- a/drivers/gpu/drm/xe/xe_guc_pc.c
> +++ b/drivers/gpu/drm/xe/xe_guc_pc.c
> @@ -992,6 +992,19 @@ static int pc_init_freqs(struct xe_guc_pc *pc)
> return ret;
> }
>
> +static int xe_guc_pc_set_strategy(struct xe_guc_pc *pc, u32 val)
> +{
> + int ret = 0;
> +
> + xe_pm_runtime_get(pc_to_xe(pc));
> + ret = pc_action_set_param(pc,
> + SLPC_PARAM_STRATEGIES,
> + val);
> + xe_pm_runtime_put(pc_to_xe(pc));
> +
> + return ret;
> +}
> +
> /**
> * xe_guc_pc_start - Start GuC's Power Conservation component
> * @pc: Xe_GuC_PC instance
> @@ -1052,6 +1065,9 @@ int xe_guc_pc_start(struct xe_guc_pc *pc)
>
> ret = pc_action_setup_gucrc(pc, GUCRC_FIRMWARE_CONTROL);
>
> + /* Enable SLPC Optimized Strategy for compute */
> + xe_guc_pc_set_strategy(pc, SLPC_OPTIMIZED_STRATEGY_COMPUTE);
> +
> out:
> xe_force_wake_put(gt_to_fw(gt), fw_ref);
> return ret;
> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
> index 9c36329fe857..88a1987ac360 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_ctx_freq_req, SLPM_GT_FREQUENCY)
> #undef MAKE_EXEC_QUEUE_POLICY_ADD
>
> static const int xe_exec_queue_prio_to_guc[] = {
> @@ -414,14 +416,19 @@ 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_ctx_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 & DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT)
> + slpc_ctx_freq_req |= SLPC_EXEC_QUEUE_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_ctx_freq_req(&policy, slpc_ctx_freq_req);
>
> xe_guc_ct_send(&guc->ct, (u32 *)&policy.h2g,
> __guc_exec_queue_policy_action_size(&policy), 0, 0);
> diff --git a/include/uapi/drm/xe_drm.h b/include/uapi/drm/xe_drm.h
> index f62689ca861a..bd0150d2200c 100644
> --- a/include/uapi/drm/xe_drm.h
> +++ b/include/uapi/drm/xe_drm.h
> @@ -1097,6 +1097,7 @@ struct drm_xe_vm_bind {
> * .engine_class = DRM_XE_ENGINE_CLASS_RENDER,
> * };
> * struct drm_xe_exec_queue_create exec_queue_create = {
> + * .flags = DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT or 0
> * .extensions = 0,
> * .vm_id = vm,
> * .num_bb_per_exec = 1,
> @@ -1110,7 +1111,6 @@ struct drm_xe_exec_queue_create {
> #define DRM_XE_EXEC_QUEUE_EXTENSION_SET_PROPERTY 0
> #define DRM_XE_EXEC_QUEUE_SET_PROPERTY_PRIORITY 0
> #define DRM_XE_EXEC_QUEUE_SET_PROPERTY_TIMESLICE 1
> -
> /** @extensions: Pointer to the first extension struct, if any */
> __u64 extensions;
>
> @@ -1123,6 +1123,7 @@ struct drm_xe_exec_queue_create {
> /** @vm_id: VM to use for this exec queue */
> __u32 vm_id;
>
> +#define DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT (0x1 << 1)
we need a way to know if the KMD version running supports it or not.
I think a bit on drm_xe_query_config would do the job.
> /** @flags: MBZ */
> __u32 flags;
>
