BFQ I/O Scheduler Patches Revised, Aiming To Be Extra Scheduler In The Kernel

BFQ developers had hoped to replace CFQ in the mainline Linux kernel with Budget Fair Queueing for a variety of reasons but it hadn't ended up making it mainline. Now the developers are hoping to introduce BFQ back to mainline as an extra available scheduler.

Paolo Valente on Wednesday published the latest patches dubbed "BFQ-v0" for adding it as an extra scheduler. He began by saying, "this new patch series turns back to the initial approach, i.e., it adds BFQ as an extra scheduler, instead of replacing CFQ with BFQ. This patch series also contains all the improvements and bug fixes recommended by Tejun, plus new features of BFQ-v8r5...On average CPUs, the current version of BFQ can handle devices performing at most ~30K IOPS; at most ~50 KIOPS on faster CPUs. These are about the same limits as CFQ. There may be room for noticeable improvements regarding these limits, but, given the overall limitations of blk itself, I thought it was not the case to further delay this new submission."

Budget Fair Queueing (BFQ) aims to provide low-latency for interactive applications and soft real-time applications, higher speed for code development tasks, high throughput, strong fairness and bandwidth/delay guarantees, and more. More details on BFQ and the early benchmarks can be found via this mailing list announcement.