powerpc/powernv: Enable POWER8 doorbell IPIs

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This patch enables POWER8 doorbell IPIs on powernv.

Since doorbells can only IPI within a core, we test to see when we can use
doorbells and if not we fall back to XICS.  This also enables hypervisor
doorbells to wakeup us up from nap/sleep via the LPCR PECEDH bit.

Based on tests by Anton, the best case IPI latency between two threads dropped
from 894ns to 512ns.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

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Michael Neuling 2014-06-11 15:59:28 +10:00 • committed by Benjamin Herrenschmidt

parent 9b6a68d943

commit d4e58e5928

5 changed files with 18 additions and 1 deletions

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2

arch/powerpc/kernel/cpu_setup_power.S

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1

arch/powerpc/platforms/powernv/Kconfig

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6

arch/powerpc/platforms/powernv/smp.c

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1

arch/powerpc/platforms/pseries/Kconfig

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9

arch/powerpc/sysdev/xics/icp-native.c

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