RTOS/AM5718: Copy to shared memory optimization

Shrihari A

Part Number: AM5718

Tool/software: TI-RTOS

Hello,

I am using AM5718 board for capturing the raw data and display. In order to process the engine in DSP from ARM, we used shared memory concept. But as we observed we were finding the copy to shared memory is taking huge amount of time which reduces the frame rate. Is it possible to reduce mm copy and can we give the access to shared memory directly for the camera capture?

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

What software are you using on ARM, resp. on DSP?

0 Shrihari A over 8 years ago in reply to Biser Gatchev-XID

Prodigy 30 points

I am using AM5718 version 4.1.0.6 and yocto build setup with omapdrmtest and dspdce-fw.

0 Rex Chang over 8 years ago in reply to Shrihari A

TI__Guru 50170 points

Hi, Shrihari,

Do you have the time measurement for the shared memory copying? The IPC performance measurement, we got around 100us round trip. The RPMSG goes through kernel context and the latency in kernel processing is in tens of usec. There were discussion of the IPC performance and alternative in e2e.ti.com/.../652242. I am not sure if the info in that thread is useful to you.

Rex

0 Shrihari A over 8 years ago in reply to Rex Chang

Prodigy 30 points

Hi Rex,

For the buffer size of 2592x1944, that we are getting from the camera, in order to copy from v4l2 buffer to shared memory it is taking 123.932ms. This is really huge as we are performing software ISP on DSP with this buffer and we have to achieve the rate of 30fps. Kindly suggest:

Is it possible to reduce by passing the buffer directly to camera instead of copying the data. As we are copying 2592x1944 raw data each time and by passing directly it would reduce the memcopy in application.
Or is there any other way to optimize the memory copy.

0 Manisha Agrawal over 8 years ago in reply to Shrihari A

TI__Mastermind 22946 points

Please allocate the memory from CMEM buffer and export that to V4l2 capture driver. That buffer can as well be shared with DSP or enable cached read/write operations. You can find the dual-camera-demo example to use CMEM buffer.

Please refer to this e2e post to take care of some known bug with that demo.

0 Rex Chang over 8 years ago in reply to Manisha Agrawal

TI__Guru 50170 points

Hi, Shrihari,

We haven't heard back from you, so I'll close this thread for now. If you have other issues down the road, please submit a new one. Thanks!

Rex

Processors

Processors forum

RTOS/AM5718: Copy to shared memory optimization