On Fri, Jul 07, 2017 at 11:23:36AM +0100, Chris Wilson wrote:
> Borrow a trick from anv, and use the last known index for the bo to skip
> a search of the batch->exec_bo when adding a new relocation. In defence
> against the bo being used in multiple batches simultaneously, we check
> that this slot exists and points back to us.
>
> v2: Also update brw_batch_references()
> v3: Reset bo->index on creation (Daniel)
>
> Signed-off-by: Chris Wilson
> Cc: Kenneth Graunke
> Cc: Matt Turner
> Cc: Jason Ekstrand
> Cc: Daniel Vetter
> ---
> src/mesa/drivers/dri/i965/brw_bufmgr.c| 1 +
> src/mesa/drivers/dri/i965/brw_bufmgr.h| 7 +++
> src/mesa/drivers/dri/i965/intel_batchbuffer.c | 18 --
> 3 files changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_bufmgr.c
> b/src/mesa/drivers/dri/i965/brw_bufmgr.c
> index da12a13152..4e43a448ae 100644
> --- a/src/mesa/drivers/dri/i965/brw_bufmgr.c
> +++ b/src/mesa/drivers/dri/i965/brw_bufmgr.c
> @@ -353,6 +353,7 @@ retry:
> p_atomic_set(&bo->refcount, 1);
> bo->reusable = true;
> bo->cache_coherent = bufmgr->has_llc;
> + bo->index = -1;
>
> pthread_mutex_unlock(&bufmgr->lock);
>
> diff --git a/src/mesa/drivers/dri/i965/brw_bufmgr.h
> b/src/mesa/drivers/dri/i965/brw_bufmgr.h
> index 4d671b6aae..27a27ca244 100644
> --- a/src/mesa/drivers/dri/i965/brw_bufmgr.h
> +++ b/src/mesa/drivers/dri/i965/brw_bufmgr.h
> @@ -76,6 +76,13 @@ struct brw_bo {
> uint64_t offset64;
>
> /**
> +* Index of this buffer inside the batch, -1 when not in a batch. Note
> +* that a single buffer may be in multiple batches (contexts), the index
> +* only refers to its last use and should not be trusted!
> +*/
> + unsigned int index;
> +
> + /**
> * Boolean of whether the GPU is definitely not accessing the buffer.
> *
> * This is only valid when reusable, since non-reusable
> diff --git a/src/mesa/drivers/dri/i965/intel_batchbuffer.c
> b/src/mesa/drivers/dri/i965/intel_batchbuffer.c
> index 62d2fe8ef3..f76ece8d71 100644
> --- a/src/mesa/drivers/dri/i965/intel_batchbuffer.c
> +++ b/src/mesa/drivers/dri/i965/intel_batchbuffer.c
> @@ -515,12 +515,20 @@ throttle(struct brw_context *brw)
> }
> }
>
> +#define READ_ONCE(x) (*(volatile __typeof__(x) *)&(x))
> +
> static void
> add_exec_bo(struct intel_batchbuffer *batch, struct brw_bo *bo)
> {
> if (bo != batch->bo) {
> - for (int i = 0; i < batch->exec_count; i++) {
> - if (batch->exec_bos[i] == bo)
> + unsigned int index = READ_ONCE(bo->index);
> +
> + if (index < batch->exec_count && batch->exec_bos[index] == bo)
> + return;
> +
> + /* May have been shared between multiple active batches */
> + for (index = 0; index < batch->exec_count; index++) {
> + if (batch->exec_bos[index] == bo)
> return;
>}
>
> @@ -553,6 +561,7 @@ add_exec_bo(struct intel_batchbuffer *batch, struct
> brw_bo *bo)
> validation_entry->rsvd1 = 0;
> validation_entry->rsvd2 = 0;
>
> + bo->index = batch->exec_count;
> batch->exec_bos[batch->exec_count] = bo;
> batch->exec_count++;
> batch->aperture_space += bo->size;
> @@ -597,6 +606,7 @@ execbuffer(int fd,
>struct brw_bo *bo = batch->exec_bos[i];
>
>bo->idle = false;
> + bo->index = -1;
>
>/* Update brw_bo::offset64 */
>if (batch->exec_objects[i].offset != bo->offset64) {
> @@ -742,6 +752,10 @@ brw_batch_has_aperture_space(struct brw_context *brw,
> unsigned extra_space)
> bool
> brw_batch_references(struct intel_batchbuffer *batch, struct brw_bo *bo)
> {
> + unsigned int index = READ_ONCE(bo->index);
> + if (index < batch->exec_count && batch->exec_bos[index] == bo)
> + return true;
Yeah that's a neat addition.
Reviewed-by: Daniel Vetter
> +
> for (int i = 0; i < batch->exec_count; i++) {
>if (batch->exec_bos[i] == bo)
> return true;
> --
> 2.13.2
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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