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| author |   Michael Neuling <mikey@neuling.org> | 2014-06-11 15:59:28 +1000 |
|---|---|---|
| committer |   Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-06-11 17:05:12 +1000 |
| commit | d4e58e5928f8c6c49228451dd03e0714cbab299a (patch) | |
| tree | 34add9a16b4dbe03da04191f51588f3f6a6bdbf9 /arch/powerpc/platforms | |
| parent | powerpc/cpuidle: Only clear LPCR decrementer wakeup bit on fast sleep entry (diff) | |
| download | linux-dev-d4e58e5928f8c6c49228451dd03e0714cbab299a.tar.xz linux-dev-d4e58e5928f8c6c49228451dd03e0714cbab299a.zip | |
powerpc/powernv: Enable POWER8 doorbell IPIs
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>
Diffstat (limited to 'arch/powerpc/platforms')
| -rw-r--r-- | arch/powerpc/platforms/powernv/Kconfig | 1 | ||||
| -rw-r--r-- | arch/powerpc/platforms/powernv/smp.c | 6 | ||||
| -rw-r--r-- | arch/powerpc/platforms/pseries/Kconfig | 1 |
3 files changed, 8 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powernv/Kconfig b/arch/powerpc/platforms/powernv/Kconfig index c252ee95bddf..45a8ed0585cd 100644 --- a/arch/powerpc/platforms/powernv/Kconfig +++ b/arch/powerpc/platforms/powernv/Kconfig @@ -17,6 +17,7 @@ config PPC_POWERNV select CPU_FREQ_GOV_USERSPACE select CPU_FREQ_GOV_ONDEMAND select CPU_FREQ_GOV_CONSERVATIVE + select PPC_DOORBELL default y config PPC_POWERNV_RTAS diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c index 0062a43a2e0d..5fcfcf44e3a9 100644 --- a/arch/powerpc/platforms/powernv/smp.c +++ b/arch/powerpc/platforms/powernv/smp.c @@ -32,6 +32,7 @@ #include <asm/opal.h> #include <asm/runlatch.h> #include <asm/code-patching.h> +#include <asm/dbell.h> #include "powernv.h" @@ -46,6 +47,11 @@ static void pnv_smp_setup_cpu(int cpu) { if (cpu != boot_cpuid) xics_setup_cpu(); + +#ifdef CONFIG_PPC_DOORBELL + if (cpu_has_feature(CPU_FTR_DBELL)) + doorbell_setup_this_cpu(); +#endif } int pnv_smp_kick_cpu(int nr) diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig index 2cb8b776c84a..756b482f819a 100644 --- a/arch/powerpc/platforms/pseries/Kconfig +++ b/arch/powerpc/platforms/pseries/Kconfig @@ -21,6 +21,7 @@ config PPC_PSERIES select HAVE_CONTEXT_TRACKING select HOTPLUG_CPU if SMP select ARCH_RANDOM + select PPC_DOORBELL default y config PPC_SPLPAR |