Latency using RMAN_assignResources()

Manisha Agrawal

Dear experts,

I have customer whose product is sensitive to latency. Customer finds that using RMAN_assignResources() to allocate buffer of large resolution size (2560x1920) causing the delay. It is okay for smaller resolution.Could you please help suggesting changes to reduce the latency for buffer allocation using RMAN_assignResources?

Regards,

Manisha

over 12 years ago

0 Ashish Kapania over 12 years ago

TI__Mastermind 21645 points

Hi Manisha,

RMAN_assignResources() is not a SYS/BIOS kernel API. I believe it is part of H.264 BP. Let me try to forward your question to the right team.

Best,

Ashish

0 GAnthony over 12 years ago

TI__Intellectual 2790 points

Manisha:

Is the latency due to video processing of large buffers, preventing other algorithms from responding in time, or is the delay in calling RMAN_assignResources() itself?

I think RMAN_assignResources() is done during algorithm creation time, so it seems the application would not be sensitive to delays during creation.

Otherwise, if the latency issue is at runtime, RMAN has some support to allow algorithms to yield to other tasks. See the discussion here:

http://processors.wiki.ti.com/index.php/Framework_Components_RMAN_Users_Guide#Cooperative_Multitasking_and_Preemption

Can you be a bit more specific on what resource is being assigned (or activated?) and where exactly the delay is (and how long)?

Thanks,

- Gil

0 Manisha Agrawal over 12 years ago in reply to GAnthony

TI__Mastermind 22946 points

Hi Gill,

The latecy that I am talking here is just coming from RMAN_assignResource. In this particular application, algorithm instance is deleted and created again run time for different codec type. It takes 500 ms to recreate algorithm instance for 2560x1920 resolution size. For smaller resolution, latency is okay.

Yelding to another task thread is not an option as it will not reduce the latency coming from decoder instance creation.

Regards,

Manisha

0 GAnthony over 12 years ago in reply to Manisha Agrawal

TI__Intellectual 2790 points

Manisha:

Can you please provide more information: Hardware platform? Software versions? What other codecs are running at the same time? Sequence of creation/deletion?

I searched the e2e forums, and found some related threads that might help:

http://e2e.ti.com/support/embedded/multimedia_software_codecs/f/356/p/229062/874063.aspx

http://e2e.ti.com/support/embedded/multimedia_software_codecs/f/356/p/103024/365404.aspx

http://processors.wiki.ti.com/index.php/IRES_HDVICP2

It may be that RMAN_assignResources() is waiting for release of some resource from a competing codec (though I believe this function doesn't normally need to block).

RMAN (http://processors.wiki.ti.com/index.php/Framework_Components_RMAN_Users_Guide) is a Framework Components module, so you can enable trace. See:

http://processors.wiki.ti.com/index.php/Trace_in_Framework_Components#Trace_in_Framework_Components

It might give an idea of which resource is causing the delay. (I'm guessing EDMA3 channels).

Regards,

- Gil

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Latency using RMAN_assignResources()