Date: Thu, 8 May 2014 20:43:39 -0700 From: Adrian Chadd <adrian@freebsd.org> To: John Baldwin <jhb@freebsd.org> Cc: Alexander Motin <mav@freebsd.org>, freebsd-current <freebsd-current@freebsd.org>, "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org> Subject: Re: [rfc] bind per-cpu timeout threads to each CPU Message-ID: <CAJ-VmonmrB7Z-PKH7P1DOJjSvFD_nRHqaiFJUuwvHoTUtiEVoQ@mail.gmail.com> In-Reply-To: <CAJ-VmonUiSeCxnbYcjtWZ8uxa0c2ys5Za_GMLQenwu8zmEuFpQ@mail.gmail.com> References: <530508B7.7060102@FreeBSD.org> <CAJ-Vmo=KFF_2tdyq1u=jNkWfEe1sR-89t3JNggf7MEvYsF%2BtQg@mail.gmail.com> <201402191602.54465.jhb@freebsd.org> <201402201417.34148.jhb@freebsd.org> <CAJ-VmonUiSeCxnbYcjtWZ8uxa0c2ys5Za_GMLQenwu8zmEuFpQ@mail.gmail.com>
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Hi, I'd like to revisit this now. I'd like to commit this stuff as-is and then take some time to revisit the catch-all softclock from cpu0 swi. It's more complicated than it needs to be as it just assumes timeout_cpu == cpuid of cpu 0. So there's no easy way to slide in a new catch-all softclock. Once that's done I'd like to then experiment with turning on the pcpu tcp timer stuff and gluing that into the RSS CPU ID / netisr ID stuff. Thanks, -a On 20 February 2014 13:48, Adrian Chadd <adrian@freebsd.org> wrote: > On 20 February 2014 11:17, John Baldwin <jhb@freebsd.org> wrote: > >> (A further variant of this would be to divorce cpu0's swi from the >> catch-all softclock and let the catch-all softclock float, but bind >> all the per-cpu swis) > > I like this idea. If something (eg per-CPU TCP timers, if it's turned > on) makes a very specific decision about the CPU then it should be > fixed. Otherwise a lot of the underlying assumptions for things like > RSS just aren't guaranteed to hold. > > It could also perhaps extend to some abstract pool of CPUs later, if > we wanted to do things like one flowing swi per socket or whatnot when > we start booting on 1024 core boxes... > > -a
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