> Il giorno 05 mar 2017, alle ore 16:16, Jens Axboe <axboe@xxxxxxxxx> ha scritto: > > On 03/04/2017 09:01 AM, Paolo Valente wrote: >> We tag as v0 the version of BFQ containing only BFQ's engine plus >> hierarchical support. BFQ's engine is introduced by this commit, while >> hierarchical support is added by next commit. We use the v0 tag to >> distinguish this minimal version of BFQ from the versions containing >> also the features and the improvements added by next commits. BFQ-v0 >> coincides with the version of BFQ submitted a few years ago [1], apart >> from the introduction of preemption, described below. >> >> BFQ is a proportional-share I/O scheduler, whose general structure, >> plus a lot of code, are borrowed from CFQ. > > I'll take a closer look at this in the coming week. ok > But one quick > comment - don't default to BFQ. Both because it might not be fully > stable yet, and also because the performance limitation of it is > quite severe. Whereas deadline doesn't really hurt single queue > flash at all, BFQ will. > Ok, sorry. I was doubtful on what to do, but, to not bother you on every details, I went for setting it as default, because I thought people would have preferred to test it, even from boot, in this preliminary stage. I reset elevator.c in the submission, unless you want me to do it even before receiving your and others' reviews. > Generally, I think that sort of logic should go into a udev rule. If > a device is rotational it should default to BFQ once the dust has > settled. > ok Looking forward for your feedback, Paolo > -- > Jens Axboe >
