[meta-xilinx] Inspecting AXI Speeds

[Giordon Stark]

Thanks for the info Matteo, I have a few questions after reading over it
since I think I'm a little lost.

- for yocto, how are you supposed to add any of the C-code to cross-compile
so it's available as a binary? Are you supposed to just add a gcc compiler
as part of the image and compile on the board directly?

- do you *need* to create a character device file first, so you have a
/dev/custom_proc which you interface with in user space through
read/write/open/close/ioctl only? I assume this is the alternative to just
having a user-space application that uses mmap entirely instead.

(all of the above was really just within the PS side)

- given that we can set things up using DMA, how do you map it on the
PL-side to the hardware you want? Is this specified by addresses, or do you
need to set up custom IP code for that instead of using the default
evaluation board block diagram?

Thanks,

Giordon

On Wed, Feb 22, 2017 at 5:35 PM Matteo Vit <
matteo.vit at dev.starwaredesign.com> wrote:

> On 22/02/2017 18:16, Giordon Stark wrote:
> > Hi Matteo,
> >
> > I'd like to (and more generally) benchmark various features of the
> > ZCU102 evaluation board. Right now, I've used meta-xilinx to compile an
> > OS that has python. It would be great to figure out how to measure the
> > AXI bus speed (such as using DMA) by running a script on the OS. It's
> > not clear to me where to start or if the default image for the
> > evaluation board will let me do this (I believe it has the necessary
> > drivers).
> >
> > Giordon
> >
> > On Wed, Feb 22, 2017 at 12:04 PM Matteo Vit
> > <matteo.vit at dev.starwaredesign.com
> > <mailto:matteo.vit at dev.starwaredesign.com>> wrote:
> >
> >     On 21/02/2017 20:07, Giordon Stark wrote:
> >     > Hi,
> >     >
> >     > If we load up an embedded OS on a Zynq board (eg: an evaluation
> >     board),
> >     > what's the best way to benchmark the AXI bus speeds and bandwidth,
> eg:
> >     > with a compiled C++ program?
> >     >
> >     > Giordon
> >     >
> >     >
> >
> >     Hi Giordon,
> >     if you mean how to measure the AXI bus speed you can use the IP block
> >     AXI performance monitor (from Xilinx).
> >
> >     If you want to know how to generate traffic on the bus, it depends on
> >     what you have connected to the AXI bus.
> >
> >     Can you please provide more details about what you'd like to achieve?
> >
> >     Regards,
> >     Matteo
> >
>
> Hi Giordon,
> I have found this interesting presentation from Xilinx about DMA control
> from user space:
>
>
> https://forums.xilinx.com/xlnx/attachments/xlnx/ELINUX/10693/1/Linux%20DMA%20from%20User%20Space-public.pdf
>
> I think this plus the AXI performance monitor is a good starting point.
>
> Regards,
> Matteo
>
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