On 2/14/21 8:17 AM, Daniel Menzel wrote: > /Somehow it seems as if I'm receiving messages from the mailing list - but mine do not seem to get through. So I'm trying again./ > > Hi, > > currently I started testing fairly fast NVMe-drives and I for the first time I dealt with the question whether the io engine is sufficient (up till now I just the default /libaio/). I found some information on io_uring online and now tried to switch to that engine: > > fio --bs=1M --rw=randwrite --numjobs=1 --iodepth=1 --size=10000M --filename=/dev/nvme0n1 --name=mylittletest --direct=1 --fsync=1 --refill_buffers --ioengine=io_uring --group_reporting --fallocate=none --runtime=60 --time_based --hipri > > But it crashes with the following information: fio: pid=2490, err=38/file:engines/io_uring.c:699, func=io_queue_init, error=Function not implemented > > My system: > > 1. fio-3.25 > 2. CentOS8 (Kernel 4.18.0-240.1.1.el8_3.x86_64) > 3. I have installed the packes liburing and liburing-devel > > Am I doing something wrong? You are not, but since you get -ENOSYS from the system call, that means that the kernel doesn't support io_uring. It was officially added with the 5.1 kernel, so 4.18 predates that. -- Jens Axboe
