| Message ID | 20210903184806.1680887-2-robdclark@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | dma-fence: Deadline awareness | expand |
On Fri, Sep 03, 2021 at 11:47:52AM -0700, Rob Clark wrote: > 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. Please add here that this callback is called without &dma_fence.lock held, and that locking is up to callers if they have some state to manage. I realized that while scratching some heads over your later patches. -Daniel > + * > + * 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 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
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);