ionice手册页说
A program running with idle io priority will only get disk time
when no other program has asked for disk io for a defined grace period.
这个“宽限期”在哪里定义？它是可见的/可调的(也许通过/ sys)？
解决方法
宽限期为250毫秒.
http://lkml.indiana.edu/hypermail/linux/kernel/0412.2/1099.html
There is an idle scheduling class,which only runs when nothing else is using the disk. A grace period is defined for which idle has to wait before getting disk access when other io has run. This defaults to 250ms currently.
您没有提供操作系统版本或发行版(是的,它确实有所作为),但RHEL / CentOS 5 6的可调参数为defined here,为/ sys / block / [device] / queue / iosched /中的fifo_expire_async(其中) [device]是sda,sdb,cciss0等.
