[RFC PATCH V2] drm/xe/guc: Use exec queue hints for GT frequency
Zeng, Oak
oak.zeng at intel.com
Thu Jan 9 17:37:01 UTC 2025
> -----Original Message-----
> From: dri-devel <dri-devel-bounces at lists.freedesktop.org> On
> Behalf Of Tejas Upadhyay
> Sent: January 9, 2025 7:07 AM
> To: intel-xe at lists.freedesktop.org
> Cc: dri-devel at lists.freedesktop.org; Nilawar, Badal
> <badal.nilawar at intel.com>; Belgaumkar, Vinay
> <vinay.belgaumkar at intel.com>; Mrozek, Michal
> <michal.mrozek at intel.com>; Morek, Szymon
> <szymon.morek at intel.com>; Souza, Jose <jose.souza at intel.com>;
> De Marchi, Lucas <lucas.demarchi at intel.com>; Upadhyay, Tejas
> <tejas.upadhyay at intel.com>
> Subject: [RFC PATCH V2] drm/xe/guc: Use exec queue hints for GT
> frequency
>
> 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 at lists.freedesktop.org
> Cc:vinay.belgaumkar at intel.com
> Cc:Michal Mrozek <michal.mrozek at intel.com>
> Cc:Szymon Morek <szymon.morek at intel.com>
> Cc:José Roberto de Souza <jose.souza 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 | 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;
You are mixing internal and external flags here. Args->flags is an external definition. Note the current value of
DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT conflict with the internal definition of:
#define EXEC_QUEUE_FLAG_PERMANENT BIT(1)
I think the better way to do it is, define an internal value for this purpose, such as:
#define EXEC_QUEUE_FLAG_LOW_LATENCY BIT(5)
Then write: if (args->flags & DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT)
flags |= EXEC_QUEUE_FLAG_LOW_LATENCY;
>
> 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,
Use internal flag also here if you do what I said above
> 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)
Use internal definition
> + slpc_ctx_freq_req |=
> SLPC_EXEC_QUEUE_FREQ_REQ_IS_COMPUTE;
From the codes above, I feel the user hint flag better be named as
Something like DRM_XE_EXEC_QUEUE_COMPUTE_HINT
I feel this is slightly better than LOW_LATENCY as low latency is a result
Of applying some frequency policy designed for compute task.
A related question is, does this new policy affect power consumption? Usually
Higher frequency implies higher power.
Do we only want to keep such frequency policy during submission time, or
Same policy is intended for whole execution time?
The answer of above question would lead to some interface design such as
Whether we need to introduce interface to disable the compute frequency policy.
> +
> __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(&polic
> y, timeslice_us);
>
> __guc_exec_queue_policy_add_preemption_timeout(&polic
> y, 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)
I wonder why flag can't start from (0x1 << 0) here.
Yes I did see the v2 comment of below:
- DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT 1 is already planned
for other hint(Szymon)
but this is regarding the definition of a flag used in exec_queue_create, and this
is the first time we use this flag in *this* uAPI. It shouldn't conflict with UMD's usage of hint flags
in *other* uAPI
> /** @flags: MBZ */
Remove this MBZ comment
Oak
> __u32 flags;
>
> --
> 2.34.1
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