[PATCH v3 2/2] drm/i915/gvt: Trigger scheduling after context complete

[Ping Gao]

The time based scheduler poll context busy status at every
micro-second during vGPU switch, it will make GPU idle for a while
when the context is very small and completed before the next
micro-second arrival. Trigger scheduling immediately after context
complete will eliminate GPU idle and improve performance.

Create two vGPU with same type, run Heaven simultaneously:
Before this patch:
 +---------+----------+----------+
 |         |  vGPU1   |   vGPU2  |
 +---------+----------+----------+
 |  Heaven |  357     |    354   |
 +-------------------------------+

After this patch:
 +---------+----------+----------+
 |         |  vGPU1   |   vGPU2  |
 +---------+----------+----------+
 |  Heaven |  397     |    398   |
 +-------------------------------+

v2: Let need_reschedule protect by gvt-lock.

Signed-off-by: Ping Gao <ping.a.gao at intel.com>
Signed-off-by: Weinan Li <weinan.z.li at intel.com>
---
 drivers/gpu/drm/i915/gvt/scheduler.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
index 6ae286c..e63b1d8 100644
--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -431,6 +431,10 @@ static void complete_current_workload(struct intel_gvt *gvt, int ring_id)
 
 	atomic_dec(&vgpu->running_workload_num);
 	wake_up(&scheduler->workload_complete_wq);
+
+	if (gvt->scheduler.need_reschedule)
+		intel_gvt_request_service(gvt, INTEL_GVT_REQUEST_EVENT_SCHED);
+
 	mutex_unlock(&gvt->lock);
 }
 
-- 
2.7.4