| Message ID | 1457693986-6892-12-git-send-email-zhi.a.wang@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Mar 11, 2016 at 06:59:42PM +0800, Zhi Wang wrote: > This patch introduces an approach to track the execlist context status > change. > > GVT-g uses GVT context as the "shadow context". The content inside GVT > context will be copied back to guest after the context is idle. So GVT-g > has to know the status of the execlist context. > > This function is configurable in the context creation service. Currently, > Only GVT-g will create the "status-change-notification" enabled GEM > context. Nope. Please hook into the lower-frequency idle mechanism then. -Chris
Hi Chirs:
Could you elaborate your idea here? :) As we have to know the status change of the LRC context, not only the request to copy the content back to guest (There will be a small window between a request is finished and the context is switched out). We tried i915_wait_request() before, looks not help... And it seems only CSB change will show the context is really idle.
-----Original Message-----
From: Chris Wilson [mailto:chris@chris-wilson.co.uk]
Sent: Friday, March 11, 2016 7:28 PM
To: Wang, Zhi A
Cc: intel-gfx@lists.freedesktop.org; igvt-g@lists.01.org; Tian, Kevin; Lv, Zhiyuan; Niu, Bing; Song, Jike; daniel.vetter@ffwll.ch; Cowperthwaite, David J; joonas.lahtinen@linux.intel.com
Subject: Re: [RFCv3 11/15] drm/i915: Introduce execlist context status change notification
On Fri, Mar 11, 2016 at 06:59:42PM +0800, Zhi Wang wrote:
> This patch introduces an approach to track the execlist context status
> change.
>
> GVT-g uses GVT context as the "shadow context". The content inside GVT
> context will be copied back to guest after the context is idle. So GVT-g
> has to know the status of the execlist context.
>
> This function is configurable in the context creation service. Currently,
> Only GVT-g will create the "status-change-notification" enabled GEM
> context.
Nope. Please hook into the lower-frequency idle mechanism then.
-Chris
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 1281bbf..68b821a 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -892,6 +892,8 @@ struct intel_context { u64 lrc_desc; uint32_t *lrc_reg_state; bool root_pointer_dirty; + bool need_status_change_notification; + struct atomic_notifier_head status_notifier_head; } engine[I915_NUM_RINGS]; struct list_head link; diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index 19c6b46..ae1ab92 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -439,6 +439,18 @@ static void execlists_submit_requests(struct drm_i915_gem_request *rq0, execlists_elsp_write(rq0, rq1); } +static inline void execlists_context_status_change( + struct intel_context *ctx, + struct intel_engine_cs *ring, + unsigned long status) +{ + if (!ctx->engine[ring->id].need_status_change_notification) + return; + + atomic_notifier_call_chain(&ctx->engine[ring->id].status_notifier_head, + status, NULL); +} + static void execlists_context_unqueue(struct intel_engine_cs *ring) { struct drm_i915_gem_request *req0 = NULL, *req1 = NULL; @@ -495,6 +507,13 @@ static void execlists_context_unqueue(struct intel_engine_cs *ring) WARN_ON(req1 && req1->elsp_submitted); + execlists_context_status_change(req0->ctx, ring, CONTEXT_SCHEDULE_IN); + + if (req1) { + execlists_context_status_change(req1->ctx, + ring, CONTEXT_SCHEDULE_IN); + } + execlists_submit_requests(req0, req1); } @@ -515,6 +534,8 @@ static bool execlists_check_remove_request(struct intel_engine_cs *ring, "Never submitted head request\n"); if (--head_req->elsp_submitted <= 0) { + execlists_context_status_change(head_req->ctx, + ring, CONTEXT_SCHEDULE_OUT); list_move_tail(&head_req->execlist_link, &ring->execlist_retired_req_list); return true; @@ -2590,6 +2611,13 @@ int __intel_lr_context_deferred_alloc(struct intel_context *ctx, } i915_add_request_no_flush(req); } + + if (params->ctx_needs_status_change_notification) { + ctx->engine[ring->id].need_status_change_notification = true; + ATOMIC_INIT_NOTIFIER_HEAD( + &ctx->engine[ring->id].status_notifier_head); + } + return 0; error_ringbuf: diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h index 528c4fb..15791d4 100644 --- a/drivers/gpu/drm/i915/intel_lrc.h +++ b/drivers/gpu/drm/i915/intel_lrc.h @@ -54,6 +54,11 @@ #define GEN8_CSB_READ_PTR(csb_status) \ (((csb_status) & GEN8_CSB_READ_PTR_MASK) >> 8) +enum { + CONTEXT_SCHEDULE_IN = 0, + CONTEXT_SCHEDULE_OUT, +}; + /* Logical Rings */ int intel_logical_ring_alloc_request_extras(struct drm_i915_gem_request *request); int intel_logical_ring_reserve_space(struct drm_i915_gem_request *request); @@ -101,6 +106,7 @@ struct intel_lr_context_alloc_params { struct intel_engine_cs *ring; u32 ringbuffer_size; bool ctx_needs_init; + bool ctx_needs_status_change_notification; }; void intel_lr_context_free(struct intel_context *ctx);
This patch introduces an approach to track the execlist context status change. GVT-g uses GVT context as the "shadow context". The content inside GVT context will be copied back to guest after the context is idle. So GVT-g has to know the status of the execlist context. This function is configurable in the context creation service. Currently, Only GVT-g will create the "status-change-notification" enabled GEM context. Signed-off-by: Zhi Wang <zhi.a.wang@intel.com> --- drivers/gpu/drm/i915/i915_drv.h | 2 ++ drivers/gpu/drm/i915/intel_lrc.c | 28 ++++++++++++++++++++++++++++ drivers/gpu/drm/i915/intel_lrc.h | 6 ++++++ 3 files changed, 36 insertions(+)