Express virtual channels: Towards the ideal interconnection fabric

Amit Kumar, Li Shiuan Peh, Partha Kundu, Niraj K. Jha

Research output: Chapter in Book/Report/Conference proceedingConference contribution

297 Scopus citations


Due to wire delay scalability and bandwidth limitations inherent in shared buses and dedicated links, packet-switched on-chip interconnection networks are fast emerging as the pervasive communication fabric to connect different processing elements in many-core chips. However, current state-of-the-art packet-switched networks rely on complex routers which increases the communication overhead and energy consumption as compared to the ideal interconnection fabric. In this paper, we try to close the gap between the state-of-the-art packet-switched network and the ideal interconnect by proposing express virtual channels (EVCs), a novel flow control mechanism which allows packets to virtually bypass intermediate routers along their path in a completely non-speculative fashion, thereby lowering the energy/delay towards that of a dedicated wire while simultaneously approaching ideal throughput with a practical design suitable for on-chip networks. Our evaluation results using a detailed cycle-accurate simulator on a range of synthetic traffic and SPLASH benchmark traces show upto 84% reduction in packet latency and upto 23% improvement in throughput while reducing the average router energy consumption by upto 38% over an existing state-of-the-art packet-switched design. When compared to the ideal interconnect, EVCs add just two cycles to the no-load latency, and are within 14% of the ideal throughput. Moreover, we show that the proposed design incurs a minimal hardware overhead while exhibiting excellent scalability with increasing network sizes.

Original languageEnglish (US)
Title of host publicationISCA'07
Subtitle of host publication34th Annual International Symposium on Computer Architecture, Conference Proceedings
Number of pages12
StatePublished - 2007
EventISCA'07: 34th Annual International Symposium on Computer Architecture - San Diego, CA, United States
Duration: Jun 9 2007Jun 13 2007

Publication series

NameProceedings - International Symposium on Computer Architecture
ISSN (Print)1063-6897


OtherISCA'07: 34th Annual International Symposium on Computer Architecture
Country/TerritoryUnited States
CitySan Diego, CA

All Science Journal Classification (ASJC) codes

  • General Engineering


  • Flow-control
  • Packet-switching
  • Router design


Dive into the research topics of 'Express virtual channels: Towards the ideal interconnection fabric'. Together they form a unique fingerprint.

Cite this