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From: Rob Clark <robdclark@gmail.com>
To: dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org
Cc: "Daniel Vetter" <daniel@ffwll.ch>,
	"Christian König" <ckoenig.leichtzumerken@gmail.com>,
	"Michel Dänzer" <michel@daenzer.net>,
	"Pekka Paalanen" <ppaalanen@gmail.com>,
	"Rob Clark" <robdclark@chromium.org>,
	"Christian König" <christian.koenig@amd.com>,
	"Sumit Semwal" <sumit.semwal@linaro.org>,
	"Gustavo Padovan" <gustavo@padovan.org>,
	linux-media@vger.kernel.org (open list:SYNC FILE FRAMEWORK),
	linux-kernel@vger.kernel.org (open list)
Subject: [PATCH v3 1/9] dma-fence: Add deadline awareness
Date: Fri,  3 Sep 2021 11:47:52 -0700	[thread overview]
Message-ID: <20210903184806.1680887-2-robdclark@gmail.com> (raw)
In-Reply-To: <20210903184806.1680887-1-robdclark@gmail.com>

From: Rob Clark <robdclark@chromium.org>

Add a way to hint to the fence signaler of an upcoming deadline, such as
vblank, which the fence waiter would prefer not to miss.  This is to aid
the fence signaler in making power management decisions, like boosting
frequency as the deadline approaches and awareness of missing deadlines
so that can be factored in to the frequency scaling.

v2: Drop dma_fence::deadline and related logic to filter duplicate
    deadlines, to avoid increasing dma_fence size.  The fence-context
    implementation will need similar logic to track deadlines of all
    the fences on the same timeline.  [ckoenig]

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/dma-buf/dma-fence.c | 20 ++++++++++++++++++++
 include/linux/dma-fence.h   | 16 ++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index ce0f5eff575d..1f444863b94d 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -910,6 +910,26 @@ dma_fence_wait_any_timeout(struct dma_fence **fences, uint32_t count,
 }
 EXPORT_SYMBOL(dma_fence_wait_any_timeout);
 
+
+/**
+ * dma_fence_set_deadline - set desired fence-wait deadline
+ * @fence:    the fence that is to be waited on
+ * @deadline: the time by which the waiter hopes for the fence to be
+ *            signaled
+ *
+ * Inform the fence signaler of an upcoming deadline, such as vblank, by
+ * which point the waiter would prefer the fence to be signaled by.  This
+ * is intended to give feedback to the fence signaler to aid in power
+ * management decisions, such as boosting GPU frequency if a periodic
+ * vblank deadline is approaching.
+ */
+void dma_fence_set_deadline(struct dma_fence *fence, ktime_t deadline)
+{
+	if (fence->ops->set_deadline && !dma_fence_is_signaled(fence))
+		fence->ops->set_deadline(fence, deadline);
+}
+EXPORT_SYMBOL(dma_fence_set_deadline);
+
 /**
  * dma_fence_init - Initialize a custom fence.
  * @fence: the fence to initialize
diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
index 6ffb4b2c6371..9c809f0d5d0a 100644
--- a/include/linux/dma-fence.h
+++ b/include/linux/dma-fence.h
@@ -99,6 +99,7 @@ enum dma_fence_flag_bits {
 	DMA_FENCE_FLAG_SIGNALED_BIT,
 	DMA_FENCE_FLAG_TIMESTAMP_BIT,
 	DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
+	DMA_FENCE_FLAG_HAS_DEADLINE_BIT,
 	DMA_FENCE_FLAG_USER_BITS, /* must always be last member */
 };
 
@@ -261,6 +262,19 @@ struct dma_fence_ops {
 	 */
 	void (*timeline_value_str)(struct dma_fence *fence,
 				   char *str, int size);
+
+	/**
+	 * @set_deadline:
+	 *
+	 * Callback to allow a fence waiter to inform the fence signaler of an
+	 * upcoming deadline, such as vblank, by which point the waiter would
+	 * prefer the fence to be signaled by.  This is intended to give feedback
+	 * to the fence signaler to aid in power management decisions, such as
+	 * boosting GPU frequency.
+	 *
+	 * This callback is optional.
+	 */
+	void (*set_deadline)(struct dma_fence *fence, ktime_t deadline);
 };
 
 void dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops,
@@ -586,6 +600,8 @@ static inline signed long dma_fence_wait(struct dma_fence *fence, bool intr)
 	return ret < 0 ? ret : 0;
 }
 
+void dma_fence_set_deadline(struct dma_fence *fence, ktime_t deadline);
+
 struct dma_fence *dma_fence_get_stub(void);
 struct dma_fence *dma_fence_allocate_private_stub(void);
 u64 dma_fence_context_alloc(unsigned num);
-- 
2.31.1


  reply	other threads:[~2021-09-03 18:44 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-03 18:47 [PATCH v3 0/9] dma-fence: Deadline awareness Rob Clark
2021-09-03 18:47 ` Rob Clark [this message]
2021-09-08 17:55   ` [PATCH v3 1/9] dma-fence: Add deadline awareness Daniel Vetter
2021-09-03 18:47 ` [PATCH v3 2/9] drm/vblank: Add helper to get next vblank time Rob Clark
2021-09-03 18:47 ` [PATCH v3 3/9] drm/atomic-helper: Set fence deadline for vblank Rob Clark
2021-09-03 18:47 ` [PATCH v3 4/9] drm/scheduler: Add fence deadline support Rob Clark
2021-09-08 17:45   ` Daniel Vetter
2021-09-09  6:22     ` Christian König
2021-09-14 13:38       ` Daniel Vetter
2021-09-21 15:57     ` Rob Clark
2021-09-21 16:35       ` Rob Clark
2021-09-21 16:45         ` Christian König
2021-09-21 20:09   ` Andrey Grodzovsky
2021-09-21 20:47     ` Rob Clark
2021-09-22  2:18       ` Andrey Grodzovsky
2021-09-22  3:32         ` Rob Clark
2021-09-22 14:31           ` Andrey Grodzovsky
2021-09-22 15:01             ` Rob Clark
2021-09-03 18:47 ` [PATCH v3 5/9] drm/msm: Add deadline based boost support Rob Clark
2021-09-08 17:48   ` Daniel Vetter
2021-09-08 17:57     ` Rob Clark
2021-09-03 18:47 ` [PATCH v3 6/9] dma-buf/fence-array: Add fence deadline support Rob Clark
2021-09-08 18:00   ` Daniel Vetter
2021-09-09  6:55     ` Christian König
2021-09-03 18:47 ` [PATCH v3 7/9] dma-buf/fence-chain: " Rob Clark
2021-09-08 17:54   ` Daniel Vetter
2021-09-08 18:19     ` Rob Clark
2021-09-08 18:45       ` Daniel Vetter
2021-09-09  6:31         ` Christian König
2021-09-03 18:47 ` [PATCH v3 8/9] dma-buf/sync_file: Add SET_DEADLINE ioctl Rob Clark
2021-09-08 17:50   ` Daniel Vetter
2021-09-08 18:23     ` Rob Clark
2021-09-08 18:49       ` Daniel Vetter
2021-09-08 19:40         ` Rob Clark
2021-09-08 21:10           ` Daniel Vetter
2021-09-21 18:08             ` Rob Clark
2021-09-27  8:42   ` Pekka Paalanen
2021-09-27  8:53     ` Christian König
2021-09-27 14:36     ` Rob Clark
2021-09-28  7:57       ` Pekka Paalanen
2021-09-03 18:48 ` [PATCH v3 9/9] dma-buf/sw_sync: Add fence deadline support Rob Clark
2021-09-09 16:16 ` [PATCH v3 0/9] dma-fence: Deadline awareness Simon Ser
2021-09-09 16:35   ` Rob Clark
2021-09-09 16:42     ` Simon Ser
2021-09-09 17:08       ` Rob Clark

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