[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 for Xen 4.6 3/4] libxl: enabling XL to set per-VCPU parameters of a domain for RTDS scheduler
On Mon, 2015-06-08 at 15:55 -0500, Chong Li wrote: > On Mon, Jun 8, 2015 at 10:56 AM, Dario Faggioli > > So, Thoughts? What do you think the best way forward could be? > > I like option 2 more. But I think we may also need a 'vcpuid' field in > libxl_sched_params. > For sparse array support, yes. At which point, I would flip the names as well, i.e., something like this: libxl_vcpu_sched_params = Struct("vcpu_sched_params",[ ("vcpuid", integer, { xxx some init val xxx}), ("weight", integer, {'init_val': 'LIBXL_PARAM_WEIGHT_DEFAULT'}), ("cap", integer, {'init_val': 'LIBXL_PARAM_CAP_DEFAULT'}), ("period", integer, {'init_val': 'LIBXL_PARAM_PERIOD_DEFAULT'}), ("slice", integer, {'init_val': 'LIBXL_PARAM_SLICE_DEFAULT'}), ("latency", integer, {'init_val': 'LIBXL_PARAM_LATENCY_DEFAULT'}), ("extratime", integer, {'init_val': 'LIBXL_PARAM_EXTRATIME_DEFAULT'}), ("budget", integer, {'init_val': 'LIBXL_PARAM_BUDGET_DEFAULT'}), ]) libxl_sched_params = Struct("sched_params",[ ("sched", libxl_scheduler), ("vcpus", Array(libxl_sched_params, "num_vcpus")), ]) With the possibility of naming the latter 'libxl_vcpus_sched_params', which is more descriptive, but perhaps is too similar to libxl_vcpu_sched_params. Ian, George, what do you think? While we're here, another thing we would appreciate some feedback on is what should happen to libxl_domain_sched_params_get(). This occurred to my mind while reviewing patch 4 of this series. Actually, I think we've discussed this before, but can't find the reference now. Anyway, my view is that, for a scheduler that uses per-vcpu parameters, libxl_domain_sched_params_set() should set the same parameters for all the vcpus. When it comes to _get(), however, I'm not sure. To match the _set() case, we'd need to return the parameters of all the vcpus, but we can't, because the function takes a libxl_domain_sched_params argument, which just holds 1 tuple. Should we just WARN and ask, when on that specific scheduler, to use the per-vcpu variant being introduced in this patch (libxl_vcpu_sched_params_get())? This does not look ideal, but without changing the prototype of libxl_domain_sched_params_get(), I don't see what else sensible we could do... :-/ Should we change it, and do the LIBXL_API_VERSION "trick"? So, again, thoughts? Regards, Dario -- <<This happens because I choose it to happen!>> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) Attachment:
signature.asc _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |