  Since Bitcoin was first introduced in 2008, many types of cryptocurrencies
have been proposed based on blockchain. However, the performance of
permissionless blockchains restricts the widespread of cryptocurrency.
Recently, Libra was proposed by Facebook based on a permissioned blockchain,
i.e. the Libra blockchain. The vision of Libra is to become a global currency
supporting financial applications, but it is doubted whether the performance of
the Libra blockchain is able to support frequent micropayment scenarios. In
this paper, we propose a methodology to evaluate the performance of blockchain
platforms and conducted an experimental study on the Libra blockchain. The
results show that the Libra blockchain can only process about one thousand
transactions per second at most, and the performance drops significantly as the
number of validators increases. Although it outperforms permissionless
blockchain platforms, the performance of the Libra blockchain is still
unsatisfactory compared to other permissioned blockchains like Hyperledger
Fabric and needs to make effective improvements in order to support global
micropayment in the future.
