On 03/01/2018 12:23 AM, Michael Lyle wrote: > On 01/02/2018 12:53 AM, tang.junhui@xxxxxxxxxx wrote: >> If no front-end I/O coming, would this cause write-back IOs one by one >> (one write-back IO issued must after the completion of the previous IO)? >> though with zero delay time, is the write-back performance still good? > Hi Mike, > Yes-- this speeds up writeback during idle from 4k/sec to about 10MB/sec > on my slow 5400RPM disk. (It writes back at about 20MB/sec with deep > queues in the same scenario). So in this case it's about 2500x faster > than current idle writeback, but half as fast as writeback with full > device utilization. > Nice performance data! > With only one I/O outstanding at a time, if front-end I/O starts latency > for the first request is still good. It is good idea, I like it. Acked-by: Coly Li <colyli@xxxxxxx> Thanks for the effort :-) Coly Li
