[dpdk-users] dpdk - for video frames too ?

[dpdk-users] dpdk - for video frames too ?

[Ran Shalit]

Hello,

I hope you can assist me on the following debate.

I need to develop a driver/application which capture and output video
frames from PCIe device , and is using Intel cpu (i7), Centand Intel's
media sdk server framework for the video compression.

I am not sure what will be a better choice between the following 2 options:
1. application which use dpdk for capture and output to the PCIe device
2. v4l driver for the PCIe device

dpdk is supposed to be able to read/write from PCIe device too.
I tried to see the prons/cons of dpdk compared to v4l.

prons of dpdk, as I understand them:
1. userspace application (easier debugging compared to kernel
debugging of v4l device driver)
2. supposed better performance

cons of dpdk compared to v4l:
1. I could not find examples for PCIe device usage , or samples for
showing how application (such as media sdk) use dpdk video frames.


Thank you for any feedback on the matter,

Regards,
Ran

Re: [dpdk-users] dpdk - for video frames too ?

[Thomas Monjalon]

2015-11-12 09:14, Ran Shalit:
> I need to develop a driver/application which capture and output video
> frames from PCIe device , and is using Intel cpu (i7), Centand Intel's
> media sdk server framework for the video compression.
> 
> I am not sure what will be a better choice between the following 2 options:
> 1. application which use dpdk for capture and output to the PCIe device
> 2. v4l driver for the PCIe device
> 
> dpdk is supposed to be able to read/write from PCIe device too.
> I tried to see the prons/cons of dpdk compared to v4l.
> 
> prons of dpdk, as I understand them:
> 1. userspace application (easier debugging compared to kernel
> debugging of v4l device driver)
> 2. supposed better performance
> 
> cons of dpdk compared to v4l:
> 1. I could not find examples for PCIe device usage , or samples for
> showing how application (such as media sdk) use dpdk video frames.

There is no API for video currently.
There is an API for networking drivers and a crypto API is coming.
If you feel a DPDK poll mode driver would be a good design, you are
welcome to do it. In case it brings some performance improvement,
it can be decided (no guarantee) to integrate it in the scope of the DPDK.

Re: [dpdk-users] dpdk - for video frames too ?

[Ran Shalit]

On Thu, Nov 12, 2015 at 10:49 AM, Thomas Monjalon
<thomas.monjalon@6wind.com> wrote:
> 2015-11-12 09:14, Ran Shalit:
>> I need to develop a driver/application which capture and output video
>> frames from PCIe device , and is using Intel cpu (i7), Centand Intel's
>> media sdk server framework for the video compression.
>>
>> I am not sure what will be a better choice between the following 2 options:
>> 1. application which use dpdk for capture and output to the PCIe device
>> 2. v4l driver for the PCIe device
>>
>> dpdk is supposed to be able to read/write from PCIe device too.
>> I tried to see the prons/cons of dpdk compared to v4l.
>>
>> prons of dpdk, as I understand them:
>> 1. userspace application (easier debugging compared to kernel
>> debugging of v4l device driver)
>> 2. supposed better performance
>>
>> cons of dpdk compared to v4l:
>> 1. I could not find examples for PCIe device usage , or samples for
>> showing how application (such as media sdk) use dpdk video frames.
>
> There is no API for video currently.
> There is an API for networking drivers and a crypto API is coming.
> If you feel a DPDK poll mode driver would be a good design, you are
> welcome to do it. In case it brings some performance improvement,
> it can be decided (no guarantee) to integrate it in the scope of the DPDK.

Hi Thomas,

I've reply for a message posted some time ago.
Is dpdk capable of recieveing and sending buffers from PCIe using DMAs ?
I think that if the buffers represent video or not is less important,
because the important thing is to be capable to stream buffers from
(or to) the PCIe device.
Do you think it is ready to be used for such purpose ?
I ask becuase I try to see which alternative is better v4l2 or dpdk.
Dpdk can be used from userspace which in my opinion is great
advantage, but if it can't do these streaming of buffers from PCIe,
than probably I should stick with v4l2 development.

Best Regards,
Ran

Re: [dpdk-users] dpdk - for video frames too ?

[Thomas Monjalon]

Hi,

The dev mailing list is more appropriate for this discussion.

2015-12-04 18:30, Ran Shalit:
> On Thu, Nov 12, 2015 at 10:49 AM, Thomas Monjalon
> <thomas.monjalon@6wind.com> wrote:
> > 2015-11-12 09:14, Ran Shalit:
> >> I need to develop a driver/application which capture and output video
> >> frames from PCIe device , and is using Intel cpu (i7), Centand Intel's
> >> media sdk server framework for the video compression.
> >>
> >> I am not sure what will be a better choice between the following 2 options:
> >> 1. application which use dpdk for capture and output to the PCIe device
> >> 2. v4l driver for the PCIe device
> >>
> >> dpdk is supposed to be able to read/write from PCIe device too.
> >> I tried to see the prons/cons of dpdk compared to v4l.
> >>
> >> prons of dpdk, as I understand them:
> >> 1. userspace application (easier debugging compared to kernel
> >> debugging of v4l device driver)
> >> 2. supposed better performance
> >>
> >> cons of dpdk compared to v4l:
> >> 1. I could not find examples for PCIe device usage , or samples for
> >> showing how application (such as media sdk) use dpdk video frames.
> >
> > There is no API for video currently.
> > There is an API for networking drivers and a crypto API is coming.
> > If you feel a DPDK poll mode driver would be a good design, you are
> > welcome to do it. In case it brings some performance improvement,
> > it can be decided (no guarantee) to integrate it in the scope of the DPDK.
> 
> Hi Thomas,
> 
> I've reply for a message posted some time ago.
> Is dpdk capable of recieveing and sending buffers from PCIe using DMAs ?

Of course yes.

> I think that if the buffers represent video or not is less important,
> because the important thing is to be capable to stream buffers from
> (or to) the PCIe device.
> Do you think it is ready to be used for such purpose ?

You need to write a driver for your device.
Then your application needs an video API in DPDK.

> I ask becuase I try to see which alternative is better v4l2 or dpdk.
> Dpdk can be used from userspace which in my opinion is great
> advantage, but if it can't do these streaming of buffers from PCIe,
> than probably I should stick with v4l2 development.

I think your development would be welcome in DPDK.