Link, Switch Question:

[mark486]

Hi,
I modified the led-demo (XC-2). Send 44byte chanend on a Core3 to Core0, this takes ~2.6 microseconds! is it realistic? Is the max speed? -> ~15Mbyte/sek

is the internal link speed always equal to the external?
Somewhere there's sample-source-code to configure switch and link?

Mark

[Bianco]

Hello,

The bandwidth between cores on a G4 is as large as the ISA can handle.
The speed between two different chips using XMOS Links is lower.

If you use XC and regular channels, data objects will be transmitted with a handshake.
This means that if you send over characters one by one (44 times) it will do a handshake for each character and thus have a large overhead (80% in that case). Try to redo your test with a streaming channel.

[lilltroll]

You can also add the use of reinterpretation, e.g. allocate

unsigned data[11];

for(int i=0;i<44;i++)
(data,char [])='0'+i; //reinterpret data as a char[]


#pragma unsafe arrays
for(int i=0;i<11;i++)
c<:data;

You can also use master{} and slave{} to form a package of data, if you cannot allocate a streaming channel.