eMesh buffering?
Posted: Sun Sep 22, 2013 11:01 pm
Hi all,
I couldn't find this answer anywhere in the docs or the forums, so here's my question:
How do the eMesh router nodes handle message buffering / flow control (or is there a mechanism which obviates this)? If a node has multiple messages headed in the same outbound direction on a single mesh (e.g.: relaying a message from the west node to the next-hop east, relaying a message from the north node to the next-hop east, and sending a message from the local core to the next-hop east, all on <some> mesh), how is access to the outbound mesh arbitrated, and how much buffering for the loosing messages is provided (or how are the loosing messages flow controlled)? (Assuming that messages always make forward progress towards the destination, never routing away for traffic - is this also a correct assumption?)
The Epiphany Architecture Reference mentions round-robin arbitration (sec 5.5) and fixed-priority arbitration (sec 6.3), but these aren't clear to me in terms of message buffering vs flow control, etc. Can anyone shed more light on this?
Also, there's a minor bug in that doc on page 25 (Rev 3.12.12.18): the column headings in Table 3 for Address-Row and Address-Column are swapped, relative to the contents of the table.
Thanks in advance
-frank
I couldn't find this answer anywhere in the docs or the forums, so here's my question:
How do the eMesh router nodes handle message buffering / flow control (or is there a mechanism which obviates this)? If a node has multiple messages headed in the same outbound direction on a single mesh (e.g.: relaying a message from the west node to the next-hop east, relaying a message from the north node to the next-hop east, and sending a message from the local core to the next-hop east, all on <some> mesh), how is access to the outbound mesh arbitrated, and how much buffering for the loosing messages is provided (or how are the loosing messages flow controlled)? (Assuming that messages always make forward progress towards the destination, never routing away for traffic - is this also a correct assumption?)
The Epiphany Architecture Reference mentions round-robin arbitration (sec 5.5) and fixed-priority arbitration (sec 6.3), but these aren't clear to me in terms of message buffering vs flow control, etc. Can anyone shed more light on this?
Also, there's a minor bug in that doc on page 25 (Rev 3.12.12.18): the column headings in Table 3 for Address-Row and Address-Column are swapped, relative to the contents of the table.
Thanks in advance
-frank