What you want to look at is performance share and not system share. By performance share Gigabit Ethernet is just 12.6%. There are a number of Gigabit Ethernet systems but they are not contributing useful work.
There has also been some discussion lately that Rmax, the performance indicator of Top500 has started to diverge from sustained performance. Sustained performance is a general term for actual science produced with a machine as opposed to performing well on the LINPACK benchmark.
Edit: There is also a huge difference running Gigabit Ethernet over short spans as opposed to over the Internet. Latency as opposed to bandwidth is the limiting factor for many algorithms. Light takes a lot less time to travel across the aisle as opposed to across the continent.
There has also been some discussion lately that Rmax, the performance indicator of Top500 has started to diverge from sustained performance. Sustained performance is a general term for actual science produced with a machine as opposed to performing well on the LINPACK benchmark.
Edit: There is also a huge difference running Gigabit Ethernet over short spans as opposed to over the Internet. Latency as opposed to bandwidth is the limiting factor for many algorithms. Light takes a lot less time to travel across the aisle as opposed to across the continent.