Messages in this thread | | | Subject | Re: [RFC][Patch v1 1/3] sched/isolation: API to get num of hosekeeping CPUs | From | Nitesh Narayan Lal <> | Date | Tue, 22 Sep 2020 17:15:28 -0400 |
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On 9/22/20 4:58 PM, Frederic Weisbecker wrote: > On Tue, Sep 22, 2020 at 09:50:55AM -0400, Nitesh Narayan Lal wrote: >> On 9/22/20 6:08 AM, Frederic Weisbecker wrote: >> TBH I don't have a very strong case here at the moment. >> But still, IMHO, this will force the user to have both managed irqs and >> nohz_full in their environments to avoid these kinds of issues. Is that how >> we would like to proceed? > Yep that sounds good to me. I never know how much we want to split each and any > of the isolation features but I'd rather stay cautious to separate HK_FLAG_TICK > from the rest, just in case running in nohz_full mode ever becomes interesting > alone for performance and not just latency/isolation.
Fair point.
> > But look what you can do as well: > > diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c > index 5a6ea03f9882..9df9598a9e39 100644 > --- a/kernel/sched/isolation.c > +++ b/kernel/sched/isolation.c > @@ -141,7 +141,7 @@ static int __init housekeeping_nohz_full_setup(char *str) > unsigned int flags; > > flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU | > - HK_FLAG_MISC | HK_FLAG_KTHREAD; > + HK_FLAG_MISC | HK_FLAG_KTHREAD | HK_FLAG_MANAGED_IRQ; > > return housekeeping_setup(str, flags); > } > > > "nohz_full=" has historically gathered most wanted isolation features. It can > as well isolate managed irqs.
Nice, yeap this will work.
> > >>> And then can we rename it to housekeeping_num_online()? >> It could be just me, but does something like hk_num_online_cpus() makes more >> sense here? > Sure, that works as well.
Thanks a lot for all the help.
> > Thanks. > -- Nitesh
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