It's good to be near the top of the list.
As for the embargo's likely effectiveness, #1 on the Top500 list happens to be China's Sunway TaihuLight at the National Supercomputing Center in Wuxi. It sustains a performance of 93 petaflops using 10,649,600 cores, all of them 1.45GHz Sunway (also rendered ShenWay) SW26010 devices, which fit Dongarra's description of "lightweight" processors. And all were made in China.
(Insider Story)