[PATCH v6 5/7] drm/i915/gvt: add basic function for weight control

[Tian, Kevin]

> From: Ping Gao
> Sent: Thursday, March 30, 2017 12:37 AM
> 
> This method tries to guarantee precision in second level, with the adjustment
> conducted in every 100ms. At the end of each vGPU switch calculate the
> sched time and subtract it from the time slice allocated; the allocated time
> slice for every 100ms together with remaining timeslice, will be used to
> decide how much timeslice allocated to this vGPU in the next 100ms slice,
> with the end goal to guarantee weight ratio in second level.
> 
> Signed-off-by: Ping Gao <ping.a.gao at intel.com>

Reviewed-by: Kevin Tian <kevin.tian at intel.com>, with one small comment:

> +static void gvt_balance_timeslice(struct gvt_sched_data *sched_data) {
> +	struct vgpu_sched_data *vgpu_data;
> +	struct list_head *pos;
> +	static uint64_t stage_check;
> +	int stage = stage_check++ % GVT_TS_BALANCE_STAGE_NUM;
> +
> +	/* The timeslice accumulation reset at stage 0, it
> +	 * been allocated again without add the left/debt before.

which is allocated again without adding previous debt.

> +	 */
> +	if (stage == 0) {
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