Messages in this thread | | | Date | Sun, 22 Feb 2015 11:37:09 +0100 | From | Ingo Molnar <> | Subject | Re: smp_call_function_single lockups |
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* Daniel J Blueman <daniel@numascale.com> wrote:
> The Intel SDM [1] and AMD F15h BKDG [2] state that IPIs > are queued, so the wait_icr_idle() polling is only > necessary on PPro and older, and maybe then to avoid > delivery retry. This unnecessarily ties up the IPI > caller, so we bypass the polling in the Numachip APIC > driver IPI-to-self path.
It would be nice to propagate this back to the generic x86 code.
> On Linus's earlier point, with the large core counts on > Numascale systems, I previously implemented a shortcut to > allow single IPIs to bypass all the cpumask generation > and walking; it's way down on my list, but I'll see if I > can generalise and present a patch series at some point > if interested?
I am definitely interested!
Thanks,
Ingo
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