Jean-loup Gailly: <[email protected]>: >> The bandwidth seems not a problem but how about the latency or delay? > >You are right, latency might be an issue. Trying udp is on my (large) list >of things to do. > >> That is, usual 1 Giga bit Ethernet? Sorry for asking again, >> because HPC clusters' standard is 10 Giga bit or more. > >If the main issue is latency and not bandwidth, there should not be a big >difference between 1Gbit and 10 Gbit Ethernet.
Not ignorable. Since all modern switches use store-and-forward architecture, the delay time caused by a switch is almost proportional to the (packet-size / bandwidth). For example, the latencies of my GbE switch (Allied Telesis GS900-16; $200) are 2.8 and 4.5 microsecond with 1000 and 100 Mbps connections, respectively, for a 64-byte packet. Assuming the packet-size is 9 kB (jumbo packet), the latency for 1000 Mbps connection is about 72 microsecond, where that of a low-latency 10 GbE switch (Fujitsu XG700; $25000) is estimated about 7 microsecond. Hum, in 70 microsecond, almost all strong programs can do less than one simulation on 19x19 but some on 9x9, right? >Of course some other >network architectures, such as used by Mogo, can help a lot but I am >not using this. Broadcasting (O(1)) is always better than binary-tree rounting of multiple tcp connections (O(log n)), isn't it? Hideki -- Hideki Kato <mailto:[email protected]> _______________________________________________ Computer-go mailing list [email protected] http://dvandva.org/cgi-bin/mailman/listinfo/computer-go
