>>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)
>> /** @flags: MBZ */
>> __u32 flags;
>>
>>--
>>2.34.1
>>"
Acked-by: Michal Mrozek <michal.mrozek@xxxxxxxxx>
