Re: [EXTERNAL] Re: [PATCH] sync_file: Return reasonable timestamp when merging signaled fences
On Thu, May 09, 2019 at 12:46:05PM +0100, Chris Wilson wrote:
> Quoting Michael Yang (2019-05-09 05:34:11)
> > If all the sync points were signaled in both fences a and b,
> > there was only one sync point in merged fence which is a_fence[0].
> > The Fence structure in android framework might be confused about
> > timestamp if there were any sync points which were signaled after
> > a_fence[0]. It might be more reasonable to use timestamp of last signaled
> > sync point to represent the merged fence.
> > The issue can be found from EGL extension ANDROID_get_frame_timestamps.
> > Sometimes the return value of EGL_READS_DONE_TIME_ANDROID is head of
> > the return value of EGL_RENDERING_COMPLETE_TIME_ANDROID.
> > That means display/composition had been completed before rendering
> > was completed that is incorrect.
> >
> > Some discussion can be found at:
> > https://urldefense.proofpoint.com/v2/url?u=https-3A__android-2Dreview.googlesource.com_c_kernel_common_-2B_907009=DwIFaQ=bq9ppmgvSw3oQFfR871D_w=Ngg6vhouPkgwSIbDMU7rDN0ZfT2Qax50xuWkXXqQ3zw=N9R9dXGJ3zk0e0gXNM4tsiro7xCOLlWx6c3HAEseSSw=6sY2t9i2wvylWH-rPUlvY1MIuWKjCPzT8SeCgpZOIGk=
> >
> >
> > Signed-off-by: Michael Yang
> > ---
> > Hi,
> > I didn't get response since I previously sent this a month ago.
> > Could someone have a chance to look at it please?
> > Thanks.
> > drivers/dma-buf/sync_file.c | 25 +++--
> > 1 file changed, 23 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
> > index 4f6305c..d46bfe1 100644
> > --- a/drivers/dma-buf/sync_file.c
> > +++ b/drivers/dma-buf/sync_file.c
> > @@ -274,8 +274,29 @@ static struct sync_file *sync_file_merge(const char
> > *name, struct sync_file *a,
> > for (; i_b < b_num_fences; i_b++)
> > add_fence(fences, , b_fences[i_b]);
> >
> > - if (i == 0)
> > - fences[i++] = dma_fence_get(a_fences[0]);
> > + /* If all the sync pts were signaled, then adding the sync_pt who
> > +* was the last signaled to the fence.
> > +*/
> > + if (i == 0) {
> > + struct dma_fence *last_signaled_sync_pt = a_fences[0];
> > + int iter;
> > +
> > + for (iter = 1; iter < a_num_fences; iter++) {
>
> If there is more than one fence, sync_file->fence is a fence_array and
> its timestamp is what you want. If there is one fence, sync_file->fence
> is a pointer to that fence, and naturally has the right timestamp.
>
> In short, this should be handled by dma_fence_array_create() when given
> a complete set of signaled fences, it too should inherit the signaled
> status with the timestamp being taken from the last fence. It should
> also be careful to inherit the error status.
> -Chris
Thanks Chris for the inputs. For this case, there will be only one fence
in sync_file->fence after doing sync_file_merge(). Regarding to the current
implementation, dma_fence_array_create() is not called as num_fences is equal
to 1. I was wondering do you suggest that we pass a complete set of signaled
fences to sync_file_set_fence() and handle it in dma_fence_array_create().
Thanks.
- Michael
[PATCH] sync_file: Return reasonable timestamp when merging signaled fences
If all the sync points were signaled in both fences a and b,
there was only one sync point in merged fence which is a_fence[0].
The Fence structure in android framework might be confused about
timestamp if there were any sync points which were signaled after
a_fence[0]. It might be more reasonable to use timestamp of last signaled
sync point to represent the merged fence.
The issue can be found from EGL extension ANDROID_get_frame_timestamps.
Sometimes the return value of EGL_READS_DONE_TIME_ANDROID is head of
the return value of EGL_RENDERING_COMPLETE_TIME_ANDROID.
That means display/composition had been completed before rendering
was completed that is incorrect.
Some discussion can be found at:
https://android-review.googlesource.com/c/kernel/common/+/907009
Signed-off-by: Michael Yang
---
Hi,
I didn't get response since I previously sent this a month ago.
Could someone have a chance to look at it please?
Thanks.
drivers/dma-buf/sync_file.c | 25 +++--
1 file changed, 23 insertions(+), 2 deletions(-)
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index 4f6305c..d46bfe1 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -274,8 +274,29 @@ static struct sync_file *sync_file_merge(const char *name,
struct sync_file *a,
for (; i_b < b_num_fences; i_b++)
add_fence(fences, , b_fences[i_b]);
- if (i == 0)
- fences[i++] = dma_fence_get(a_fences[0]);
+ /* If all the sync pts were signaled, then adding the sync_pt who
+* was the last signaled to the fence.
+*/
+ if (i == 0) {
+ struct dma_fence *last_signaled_sync_pt = a_fences[0];
+ int iter;
+
+ for (iter = 1; iter < a_num_fences; iter++) {
+ if (ktime_compare(last_signaled_sync_pt->timestamp,
+ a_fences[iter]->timestamp) < 0) {
+ last_signaled_sync_pt = a_fences[iter];
+ }
+ }
+
+ for (iter = 0; iter < b_num_fences; iter++) {
+ if (ktime_compare(last_signaled_sync_pt->timestamp,
+ b_fences[iter]->timestamp) < 0) {
+ last_signaled_sync_pt = b_fences[iter];
+ }
+ }
+
+ fences[i++] = dma_fence_get(last_signaled_sync_pt);
+ }
if (num_fences > i) {
nfences = krealloc(fences, i * sizeof(*fences),
--
2.7.4
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[PATCH] sync_file: Return reasonable timestamp when merging signaled fences
If all the sync points were signaled in both fences a and b,
there was only one sync point in merged fence which is a_fence[0].
The Fence structure in android framework might be confused about
timestamp if there were any sync points which were signaled after
a_fence[0]. It might be more reasonable to use timestamp of last signaled
sync point to represent the merged fence.
The issue can be found from EGL extension ANDROID_get_frame_timestamps.
Sometimes the return value of EGL_READS_DONE_TIME_ANDROID is head of
the return value of EGL_RENDERING_COMPLETE_TIME_ANDROID.
That means display/composition had been completed before rendering
was completed that is incorrect.
Some discussion can be found at:
https://android-review.googlesource.com/c/kernel/common/+/907009
Signed-off-by: Michael Yang
---
drivers/dma-buf/sync_file.c | 25 +++--
1 file changed, 23 insertions(+), 2 deletions(-)
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index 4f6305c..d46bfe1 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -274,8 +274,29 @@ static struct sync_file *sync_file_merge(const char *name,
struct sync_file *a,
for (; i_b < b_num_fences; i_b++)
add_fence(fences, , b_fences[i_b]);
- if (i == 0)
- fences[i++] = dma_fence_get(a_fences[0]);
+ /* If all the sync pts were signaled, then adding the sync_pt who
+* was the last signaled to the fence.
+*/
+ if (i == 0) {
+ struct dma_fence *last_signaled_sync_pt = a_fences[0];
+ int iter;
+
+ for (iter = 1; iter < a_num_fences; iter++) {
+ if (ktime_compare(last_signaled_sync_pt->timestamp,
+ a_fences[iter]->timestamp) < 0) {
+ last_signaled_sync_pt = a_fences[iter];
+ }
+ }
+
+ for (iter = 0; iter < b_num_fences; iter++) {
+ if (ktime_compare(last_signaled_sync_pt->timestamp,
+ b_fences[iter]->timestamp) < 0) {
+ last_signaled_sync_pt = b_fences[iter];
+ }
+ }
+
+ fences[i++] = dma_fence_get(last_signaled_sync_pt);
+ }
if (num_fences > i) {
nfences = krealloc(fences, i * sizeof(*fences),
--
2.7.4
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