I'm running geth for the first time with:
geth --testnet
I can see it downloading the blockchain and it's showing progress with logs like
core/blockchain.go:1047] imported 311 blocks, 2940 txs (646.960 Mg│total 16
) in 6.924s (93.431 Mg/s). #76545 [f42c1bd1… / d1e25194…]
What is mg here?