其中一个原因是，程序员很难对并行进程的交互过程有全面和一致的认识。
One reason for this is the difficulty programmers have in obtaining a coherent and comprehensive view of the interactions of concurrent processes.
每个onbar命令的最大并行进程数由配置参数BAR_MAX_BACKUP控制。
The maximum number of parallel processes for each onbar command is controlled by the configuration parameter BAR_MAX_BACKUP.
有了微线程，我们就可能在目前中等性能的 PC 机上运行数以万计的并行进程，还可以每秒钟几十万次地在上下文之间切换。
With microthreads, it is possible to run tens of thousands of parallel processes on a moderately capable modern PC, and to switch between contexts hundreds of thousands of times every second.
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