On Wed, Apr 22, 2015 at 1:15 AM, mark.d.gray <mark.d.g...@intel.com> wrote: > Pravin Shelar wrote: >> >> On Tue, Apr 21, 2015 at 7:30 PM, Jesse Gross <je...@nicira.com> wrote: >> >>> On Tue, Apr 21, 2015 at 7:23 PM, Pravin Shelar <pshe...@nicira.com> >>> wrote: >>> >>>> On Tue, Apr 21, 2015 at 6:33 PM, Ethan Jackson <et...@nicira.com> wrote: >>>> >>>>> I really don't think this should be configurable, I can't imagine a >>>>> situation in which a user would have enough knowledge to tweak the >>>>> knob correctly. I think the only reason we'd want to configure it is >>>>> the current EMC size is too small at the moment. My preference would >>>>> be to figure out how to make it bigger, i.e. by doing prefetching and >>>>> what not. >>>>> >>>> >>>> It does depends on amount of memory available in system which can vary >>>> alot in practice. If you have lot of memory and few devices user can >>>> configure bigger EMC accordingly. Thats why it could be useful to make >>>> it configurable at vswitchd startup time. >>> >>> >>> Can't these be detected and data structures sized automatically? OVS >>> already has a ton of configuration knobs so I agree with Ethan that it >>> is not helpful to further push this onto the user who is not going to >>> understand this. >> >> >> >> I am fine with automatically configuring it at boot up. I missed that >> is what Ethan was referring. > > > A user may not have all the information required to make a decision like > that but a cloud orchestrator would. It could make a decision along the > lines of - "I have 10 virtual machines on theis compute node and I want to > allocate about 27Ms of L3 cache for the VMs and the rest for Open vSwitch > which will allow me to hit my SLA". In this case, having a runtime > configurable option would be desireable.
I can't say that I agree with this statement for the vast majority of use cases. Expecting to have that tight control over workloads and hardware configurations (not to mention understanding by the administrator) isn't really realistic outside of a benchmark or hermetically sealed box. If you want to make data structures sized based on various factors that you think might affect performance, that is fine with me. However, please do it automatically so that all users can benefit from it rather just a small minority. In general, I think this is the direction that the DPDK extensions to OVS need to move before it can become more widely deployed. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
