> Il giorno 5 mar 2019, alle ore 17:42, Paolo Valente <paolo.valente@xxxxxxxxxx> ha scritto: > > > >> Il giorno 5 mar 2019, alle ore 17:18, stan <upaitag@xxxxxxxx> ha scritto: >> >> On Tue, 5 Mar 2019 14:07:15 +0000 >> Alan Jenkins <alan.christopher.jenkins@xxxxxxxxx> wrote: >> >>> On 13/12/2018, Laura Abbott <labbott@xxxxxxxxxx> wrote: >>>> >>>> Thanks for starting this discussion. Based on this thread and >>>> other discussions, I'm going to see about enabling BFQ for >>>> 4.21. Once 4.21-rc1 comes out (i.e. almost all configs should >>>> be in) we can review the settings and see if anything needs >>>> to be adjusted. If I get some time before then (i.e. before >>>> I leave for holiday) I'll see if I can change the defaults. >>>> >>>> Laura >>> >>> Are there any more up-to-date details on this? Specifically I am >>> wondering if there will be any separate package providing udev rules, >>> that people should be aware of, if they want to provide testing of 5.0 >>> kernels for Fedora. >> >> I've been using the 5.0 kernels locally compiled and optimized for my >> hardware with bfq enabled. I don't have multi thread hardware. The >> performance has been comparable to cfq, or slightly worse. >> Subjective. > > I started testing 5.0 today too, with incredibly bad performance, on > an old Intel Core i7-2760QM@2.40GHz. I found out the bottleneck to be > the CPU (about 7x slowdown). After reporting this issue to some Linaro > guys (in CC), I've been suggested a tiresome bisection w.r.t. 4.20 > (4.20 which works with no issue). I hope someone will show up with > the cause of the problem, relieving me of this burden :) > > At any rate, let me take this opportunity for updating you guys on > what happened in the last months. > > First, server-side, I discovered that the techniques used to guarantee > I/O bandwidth to clients, containers and virtual machines easily > result in throughput losses of up to 90%! So I improved BFQ so as to > make it an alternative solution that brings this loss down to just > 10%. Full details in this very recent (today :) ) short article: > http://ow.ly/vsrW50mBAGl > One question, hoping that it is not off topic here. As a consequence of the above article, I've been asked what distros already use bfq, on Kubernetes forums: https://discuss.kubernetes.io/t/a-solution-to-the-severe-throughput-loss-caused-by-i-o-bandwidth-management/5295/2?u=paolo What can I say about Fedora? Thanks, Paolo > Second, PC-side, I've pushed new commits for the dev version of BFQ > (I'll submit these commits for the production version, probably > tomorrow; so they'll probably be all available from 5.2). These > commits provide the following, measurable performance boost: > - up to ~80% faster application start-up times in the presence of > background workloads > - ~150% throughput boost in one of the nastiest workloads for BFQ the > one generated by dbench. The throughput is finally on pr with any > other I/O scheduler, and most likely equal to the maximum possible > throughput reachable with this test > - elimination of the 18% loss of throughput occurring with only > random reads, w.r.t. to none as I/O scheduler; there is no loss any > more; > > For any question, I'll be glad to answer, if I can, > Paolo > >> And there could be other software changes affecting this. >> >> I've recently also started using the gcc kernel-stack plugin to clean >> stack on return from kernel calls, and didn't really notice any effect >> on performance in normal usage. >> _______________________________________________ >> kernel mailing list -- kernel@xxxxxxxxxxxxxxxxxxxxxxx >> To unsubscribe send an email to kernel-leave@xxxxxxxxxxxxxxxxxxxxxxx >> Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html >> List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines >> List Archives: https://lists.fedoraproject.org/archives/list/kernel@xxxxxxxxxxxxxxxxxxxxxxx _______________________________________________ kernel mailing list -- kernel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to kernel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/kernel@xxxxxxxxxxxxxxxxxxxxxxx
