Messages in this thread | | | Date | Tue, 31 Jan 2012 15:31:31 +0100 | From | Ingo Molnar <> | Subject | Re: smp: Start up non-boot CPUs asynchronously |
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* Arjan van de Ven <arjan@infradead.org> wrote:
> On Tue, 31 Jan 2012 13:52:32 +0100 > Ingo Molnar <mingo@elte.hu> wrote: > > > > The real fix would be to make the init code depend less on each > > other, i.e. have less hotplug lock dependencies. Or, if it's > > such a hot lock for a good reason, why does spinning on it slow > > down the boot process? It really shouldnt. > > by inspection, anything that calls > get_online_cpus()/put_online_cpus() will block while a CPU is > coming up. This is used in things like kmem_cache_create()... > which is used about everywhere. (there's various other > places... more or less it's a requirement for using the > for_each_online_cpu() api correctly)
Still magic delays are not acceptable - we want to face any remaining performance problems head on, we want to understand and fix them correctly.
Thanks,
Ingo
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