[PATCH 2/2] drm/i915/gvt: Audit and shadow workload during ELSP writing

[Zhi Wang]

On 05/24/17 20:49, Ping Gao wrote:
> Let the workload audit and shadow ahead of vGPU scheduling, that
> will eliminate GPU idle time and improve performance for multi-VM.
>
> The performance of Heaven running simultaneously in 3VMs has
> improved 20% after this patch.
>
> Signed-off-by: Ping Gao <ping.a.gao at intel.com>
> ---
>   drivers/gpu/drm/i915/gvt/execlist.c  | 12 ++++++++++++
>   drivers/gpu/drm/i915/gvt/scheduler.c |  7 +++++++
>   drivers/gpu/drm/i915/gvt/scheduler.h |  1 +
>   3 files changed, 20 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gvt/execlist.c b/drivers/gpu/drm/i915/gvt/execlist.c
> index dca989e..a14cf29 100644
> --- a/drivers/gpu/drm/i915/gvt/execlist.c
> +++ b/drivers/gpu/drm/i915/gvt/execlist.c
> @@ -605,6 +605,7 @@ static int submit_context(struct intel_vgpu *vgpu, int ring_id,
>   	struct list_head *q = workload_q_head(vgpu, ring_id);
>   	struct intel_vgpu_workload *last_workload = get_last_workload(q);
>   	struct intel_vgpu_workload *workload = NULL;
> +	struct drm_i915_private *dev_priv = vgpu->gvt->dev_priv;
>   	u64 ring_context_gpa;
>   	u32 head, tail, start, ctl, ctx_ctl, per_ctx, indirect_ctx;
>   	int ret;
> @@ -668,6 +669,7 @@ static int submit_context(struct intel_vgpu *vgpu, int ring_id,
>   	workload->complete = complete_execlist_workload;
>   	workload->status = -EINPROGRESS;
>   	workload->emulate_schedule_in = emulate_schedule_in;
> +	workload->shadowed = false;
>
>   	if (ring_id == RCS) {
>   		intel_gvt_hypervisor_read_gpa(vgpu, ring_context_gpa +
> @@ -701,6 +703,16 @@ static int submit_context(struct intel_vgpu *vgpu, int ring_id,
>   		return ret;
>   	}
>
> +	/* Only audit and shadow the first workload in the queue
> +	 * as there is only one pre-allocated buf-obj for shadow.
> +	 */
> +	if (vgpu->gvt->scheduler.current_vgpu != vgpu &&
> +				list_empty(workload_q_head(vgpu, ring_id))) {
> +		mutex_lock(&dev_priv->drm.struct_mutex);
> +		intel_gvt_audit_and_shadow_workload(workload);
> +		mutex_unlock(&dev_priv->drm.struct_mutex);
> +	}
> +

Is there any reason why a pre-shadow cannot happen when current_vgpu == 
vgpu and workload q is empty?

>   	queue_workload(workload);
>   	return 0;
>   }
> diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
> index d6bfdfe..4261bd1 100644
> --- a/drivers/gpu/drm/i915/gvt/scheduler.c
> +++ b/drivers/gpu/drm/i915/gvt/scheduler.c
> @@ -184,6 +184,11 @@ int intel_gvt_audit_and_shadow_workload(struct intel_vgpu_workload *workload)
>   	struct intel_ring *ring;
>   	int ret;
>
> +	if (workload->shadowed) {
> +		ret = workload->status;
> +		return ret;
> +	}
> +
>   	shadow_ctx->desc_template &= ~(0x3 << GEN8_CTX_ADDRESSING_MODE_SHIFT);
>   	shadow_ctx->desc_template |= workload->ctx_desc.addressing_mode <<
>   				    GEN8_CTX_ADDRESSING_MODE_SHIFT;
> @@ -230,6 +235,8 @@ int intel_gvt_audit_and_shadow_workload(struct intel_vgpu_workload *workload)
>   	if (ret)
>   		goto out;
>
> +	workload->shadowed = true;
> +
>   out:
>   	workload->status = ret;
>   	return ret;
> diff --git a/drivers/gpu/drm/i915/gvt/scheduler.h b/drivers/gpu/drm/i915/gvt/scheduler.h
> index 2cd725c..575659e 100644
> --- a/drivers/gpu/drm/i915/gvt/scheduler.h
> +++ b/drivers/gpu/drm/i915/gvt/scheduler.h
> @@ -78,6 +78,7 @@ struct intel_vgpu_workload {
>   	struct drm_i915_gem_request *req;
>   	/* if this workload has been dispatched to i915? */
>   	bool dispatched;
> +	bool shadowed;
>   	int status;
>
>   	struct intel_vgpu_mm *shadow_mm;
>