Messages in this thread | | | Date | Fri, 29 Jan 2021 09:34:42 -0800 | From | Alex Belits <> | Subject | Re: [EXT] Re: [Patch v4 1/3] lib: Restrict cpumask_local_spread to houskeeping CPUs |
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On 1/29/21 06:23, Marcelo Tosatti wrote: > External Email > > ---------------------------------------------------------------------- > On Fri, Jan 29, 2021 at 08:55:20AM -0500, Nitesh Narayan Lal wrote: >> >> On 1/28/21 3:01 PM, Thomas Gleixner wrote: >>> On Thu, Jan 28 2021 at 13:59, Marcelo Tosatti wrote: >>>>> The whole pile wants to be reverted. It's simply broken in several ways. >>>> I was asking for your comments on interaction with CPU hotplug :-) >>> Which I answered in an seperate mail :) >>> >>>> So housekeeping_cpumask has multiple meanings. In this case: >>> ... >>> >>>> So as long as the meaning of the flags are respected, seems >>>> alright. >>> Yes. Stuff like the managed interrupts preference for housekeeping CPUs >>> when a affinity mask spawns housekeeping and isolated is perfectly >>> fine. It's well thought out and has no limitations. >>> >>>> Nitesh, is there anything preventing this from being fixed >>>> in userspace ? (as Thomas suggested previously). >>> Everything with is not managed can be steered by user space. >>> >>> Thanks, >>> >>> tglx >>> >> >> So, I think the conclusion here would be to revert the change made in >> cpumask_local_spread via the patch: >> - lib: Restrict cpumask_local_spread to housekeeping CPUs >> >> Also, a similar case can be made for the rps patch that went in with >> this: >> - net: Restrict receive packets queuing to housekeeping CPUs > > Yes, this is the userspace solution: > > https://lkml.org/lkml/2021/1/22/815 > > Should have a kernel document with this info and examples > (the network queue configuration as well). Will > send something. > >> + net: accept an empty mask in /sys/class/net/*/queues/rx-*/rps_cpus >> >> I am not sure about the PCI patch as I don't think we can control that from >> the userspace or maybe I am wrong? > > You mean "lib: Restrict cpumask_local_spread to housekeeping CPUs" ? >
If we want to do it from userspace, we should have something that triggers it in userspace. Should we use udev for this purpose?
-- Alex
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