On Wed, 12 Dec 2018 16:07:49 -0500 Jeff Moyer <jmoyer(a)redhat.com&gt; wrote: Thanks for your insight. Doesn't look good for my use of BFQ. That's part of the problem. BFQ doesn't appear in the list of available schedulers. When I cat that location for my disks, I see [noop]. Since CFQ does appear there if it is compiled into the kernel, I'll have to look into what is done for CFQ and see how hard it would be to patch the kernel to repeat that behavior for BFQ. My use case in not mq, so after reading one of the links in this thread about performance, I saw that BFQ gave ~20 to 30 % boost in disk io performance, and enhanced low latency performance (desktop responsiveness) for single queue. That's what I want to capture by using BFQ. I wonder if that is my problem. From what Chris said, an mq scheduler is required in order to use BFQ, whether it is for mq or single queue use. I'll try that. I normally use deadline and CFQ for scheduling. Back to the compiler. I'm surprised this is so difficult. It's been in the kernel since the 2.x series, and usually the configuration options are excellent for allowing variation in how the kernel is configured. On the plus side, I notice only slight degradation in behavior using noop scheduling. :-) Maybe I should just skip scheduling. :-D