On Thu, Jun 27 2013, xun ni wrote: > Hello, Axboe: > > I read your article about the block io layer Multi-queue support SSD on > the multi-core systems. And i do some experiment on raid5 which consist of > 5 intel ssd disks. I get code from linux-block and checked out mq. After > apply kent's patch , the raid5 system works. I tested the raid with FIO and > find that the performance is not growing. 4k read iops down from 82k to > 76k. 4k random write iops down from 14k to 9k. The latency is also down > about 8% > So my question is that any configuration or modification is needed > before testing the raid5 so that the Multi-queue method works and > performance increase?
raid5/md isn't blk-mq aware at all. So that code path isn't really changed at all. If you are seeing a change in performance, that must be because the baseline is different (blk-mq sits on top of 3.10-rc, don't know what you are comparing to). You should try 3.10-rc7 and see how that fares, and report if you are seeing a performance degredation. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
