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| author | Michael Neuling <mikey@neuling.org> | 2014-06-11 07:59:28 +0200 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2014-06-11 09:05:12 +0200 |
| commit | d4e58e5928f8c6c49228451dd03e0714cbab299a (patch) | |
| tree | 34add9a16b4dbe03da04191f51588f3f6a6bdbf9 /arch/powerpc/sysdev | |
| parent | powerpc/cpuidle: Only clear LPCR decrementer wakeup bit on fast sleep entry (diff) | |
| download | linux-d4e58e5928f8c6c49228451dd03e0714cbab299a.tar.xz linux-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/sysdev')
| -rw-r--r-- | arch/powerpc/sysdev/xics/icp-native.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/powerpc/sysdev/xics/icp-native.c b/arch/powerpc/sysdev/xics/icp-native.c index 9dee47071af8..de8d9483bbe8 100644 --- a/arch/powerpc/sysdev/xics/icp-native.c +++ b/arch/powerpc/sysdev/xics/icp-native.c @@ -26,6 +26,7 @@ #include <asm/errno.h> #include <asm/xics.h> #include <asm/kvm_ppc.h> +#include <asm/dbell.h> struct icp_ipl { union { @@ -145,7 +146,13 @@ static unsigned int icp_native_get_irq(void) static void icp_native_cause_ipi(int cpu, unsigned long data) { kvmppc_set_host_ipi(cpu, 1); - icp_native_set_qirr(cpu, IPI_PRIORITY); +#ifdef CONFIG_PPC_DOORBELL + if (cpu_has_feature(CPU_FTR_DBELL) && + (cpumask_test_cpu(cpu, cpu_sibling_mask(smp_processor_id())))) + doorbell_cause_ipi(cpu, data); + else +#endif + icp_native_set_qirr(cpu, IPI_PRIORITY); } void xics_wake_cpu(int cpu) |