Messages in this thread |  | | Date | Mon, 13 Feb 2012 12:04:59 -0800 | Subject | Re: [PATCH] Avoid mask based num_possible_cpus and num_online_cpus -v5 | From | Venki Pallipadi <> |
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On Mon, Feb 13, 2012 at 11:54 AM, Tony Luck <tony.luck@gmail.com> wrote: > On Thu, Feb 2, 2012 at 12:03 PM, Rusty Russell <rusty@rustcorp.com.au> wrote: >> IIRC playing with 3 archs boot code seemed like a recipe for disaster. >> Feel free to try to fix this in -next though, and see what breaks... > > ia64 is what breaks ... well not actually broken ... but some very > weird delays that > show up in different places depending on whether this patch is present. > > First linux-next kernel to be blessed with this patch was > next-20120210. Booting it > I see: > [ 7.164233] Switching to clocksource itc > [ 146.077315] pnp: PnP ACPI init > > An ugly 138.913 second delay. Digging in the code showed that the bad bits > happened inside stop_machine() > > Reverting just this patch makes this big delay disappear: > > [ 32.780232] Switching to clocksource itc > [ 32.832100] pnp: PnP ACPI init > > but notice that it takes 25 extra seconds to get to this point in the > boot (and while > we expect to save some time by not re-computing num_online_cpus each time we > need it ... this looks to be a lot more than I'd expect!) > > -Tony
What is NR_CPUS set to here? And how many actual CPUs are there on this machine? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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