Il giorno 5 mar 2019, alle ore 17:42, Paolo Valente paolo.valente@linaro.org ha scritto:
Il giorno 5 mar 2019, alle ore 17:18, stan upaitag@zoho.com ha scritto:
On Tue, 5 Mar 2019 14:07:15 +0000 Alan Jenkins alan.christopher.jenkins@gmail.com wrote:
On 13/12/2018, Laura Abbott labbott@redhat.com 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-cau...
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@lists.fedoraproject.org To unsubscribe send an email to kernel-leave@lists.fedoraproject.org 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@lists.fedoraproject.org