increase shared memory

[schmurfy]

Hi,
I have read a lot of posts and saw some mentions of it but I have to yet to find any real answers to:
- can I increase the shared memory space between the epiphany and the arm processor ?
- if yes is there a limit on how much memory can be shared ? (I don't need most of the 1GB for linux so I would rather be able to use it as shared memory)

And the last one is obviously: how to change the default 32MB ?
While I am sure some might disagree having a board with 1GB and only 32MB shared with the epiphany by default is a little sad.

[Gravis]

this is the thread you are looking for: viewtopic.php?t=1101&p=6938

[schmurfy]

[Gravis]

[schmurfy]

thanks

[greytery]

[Gravis]

[greytery]

Let's push those limits!! Those 'reserved' mem holes are very large indeed - and I hope we can find a way of filling them.

(As proven, I do not know what I'm talking about - but) ...
If an E16 is 4x4 and an E64 is 8x8, and if only east addressing works on the Parallella, then we're looking at access to 2x52=104MB external memory for Epiphany IV / Parallela?
Most disk caches are less than that and the IT world does not quibble, but...

If there IS a demand for increased shared memory, then we also need a way of increasing bandwidth, which means utilising one or more of the N/S/W elink channels. Some of these may/may not be visible to the Zynq.

AFAIK, ysapir is no longer directly involved (he listens).
This sounds like FPGA / MMU territory, so Fred may like to comment.

tery

[shodruk]

[Gravis]

schmurfy,
is there any particular reason that you need more than 32MB of shared memory? sure, having more is great and all but accessing shared memory from the Epiphany is slow. if you have large amounts of data then you are probably processing a data stream and should cycle the data to and from the epiphany and host, only using the shared memory as a simple buffer (until an Epiphany DMA Engine is implemented in HDL).