This patch did several jobs:
1. redefine DEFAULT_RANDOM_OPS from 1000 to 1024, which made the random IO more accurate;
2. change parameters' type of update_latency_info from struct timeval to its according pointers, which runs more effeciently;
3. blocks = io_ops;
Among this the 3rd is the most important point:
1. the former code has statistics bug in reporting random IO rate (sometimes it reports an SATA has 10,000 MB/s writing rate!): the original author just misused one variable.