On Tue, Mar 08, 2022 at 10:42:09PM -0800, Song Liu wrote: > RAID arrays check/repair operations benefit a lot from merging requests. > If we only check the previous entry for merge attempt, many merge will be > missed. As a result, significant regression is observed for RAID check > and repair. > > Fix this by checking more than just the previous entry when > plug->multiple_queues == true. But this also means really significant CPU overhead for all other workloads. > > This improves the check/repair speed of a 20-HDD raid6 from 19 MB/s to > 103 MB/s. What driver uses multiple queues for HDDs? Can you explain the workload submitted by a md a bit better? I wonder if we can easily do the right thing straight in the md driver.
