+
20161014 - Possible Directional Routing Hoplite Variant?
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EDIT: One that might not deadlock...
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+
+ +------+ +------+ +------+
+ | | | | | |
+ V | V | V |
+ +----[_]<---[_]<---[_]<---[_]<---[_]<---[_]<---+
+ | | ^ | ^ | ^ |
+ | V | V | V | |
+ +--->[_]--->[_]--->[_]--->[_]--->[_]--->[_]----+
+ | ^ | ^ | ^
+ V | V | V |
+ +----[_]<---[_]<---[_]<---[_]<---[_]<---[_]<---+
+ | | ^ | ^ | ^ |
+ | V | V | V | |
+ +--->[_]--->[_]--->[_]--->[_]--->[_]--->[_]----+
+ | ^ | ^ | ^
+ V | V | V |
+ +----[_]<---[_]<---[_]<---[_]<---[_]<---[_]<---+
+ | | ^ | ^ | ^ |
+ | V | V | V | |
+ +--->[_]--->[_]--->[_]--->[_]--->[_]--->[_]----+
+ | ^ | ^ | ^
+ | | | | | |
+ +------+ +------+ +------+
+
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+
+
Old post which would definitely deadlock...
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+
+Thinking about minimal grid based routing.
+Two things I don't like about the
Hoplite,
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+
+(1.) Full chip return paths.
+(2.) Route length not proportional to 2D locality.
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+
+Like the simplified router and crossbar.
+Wondering if there is a way to improve the routing by adjusting the fixed directions and removing the full chip return paths.
+Came up with this idea, but not sure if it is deadlock free yet.
+Likely this is well researched and has some proper name, but I'm not well learned in this area.
+
+
+--->+--->+--->+--->+--->+--->+--->+
+^ | ^ | ^ | ^ |
+| V | V | V | V
++<---+<---+<---+<---+<---+<---+<---+
+^ | ^ | ^ | ^ |
+| V | V | V | V
++--->+--->+--->+--->+--->+--->+--->+
+^ | ^ | ^ | ^ |
+| V | V | V | V
++<---+<---+<---+<---+<---+<---+<---+
+^ | ^ | ^ | ^ |
+| V | V | V | V
++--->+--->+--->+--->+--->+--->+--->+
+^ | ^ | ^ | ^ |
+| V | V | V | V
++<---+<---+<---+<---+<---+<---+<---+
+
+Hoplite is only right and down, with a full chip return to loop around.
+This is right-only on even rows, left-only on odd rows,
+then up-only on even columns, down-only on odd columns.
+Requires grid of cores to be a multiple of 2 in each dimension.
+Enables a message to quickly turn around.
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+
+Haven't fully thought through routing logic,
+but the general idea is that if a packet needs to move in a direction not supported on a row or column,
+it get routed on the other axis so it can switch direction.
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