【isca论文4】Technology-Driven, Highly-Scalable Dragonfly Topology

cybstef

abstract
Evolving technology and increasing pin-bandwidth moti-
vate the use of high-radix routers to reduce the diameter, la-
tency, and cost of interconnection networks. High-radix net-
works, however, require longer cables than their low-radix
counterparts. Because cables dominate network cost, the num-
ber of cables, and particularly the number of long, global ca-
bles should be minimized to realize an efficient network. In
this paper, we introduce the dragonfly topology which uses a
group of high-radix routers as a virtual router to increase the
effective radix of the network. With this organization, each
minimally routed packet traverses at most one global channel.
By reducing global channels, a dragonfly reduces cost by 20%
compared to a flattened butterfly and by 52% compared to a
folded Clos network in configurations with ≥ 16K nodes.
We also introduce two new variants of global adaptive rout-
ing that enable load-balanced routing in the dragonfly. Each
router in a dragonfly must make an adaptive routing decision
based on the state of a global channel connected to a different
router. Because of the indirect nature of this routing decision,
conventional adaptive routing algorithms give degraded per-
formance. We introduce the use of selective virtual-channel
discrimination and the use of credit round-trip latency to both
sense and signal channel congestion. The combination of these
two methods gives throughput and latency that approaches
that of an ideal adaptive routing algorithm.

cybstef

论坛出问题了，怎么第一次发附件都连接不进去？

cybstef

cybstef

yaogeili
版主帮忙，我怎么传不了附件了。

cybstef

为什么没有人理？