From 8b9951ed7e5b517bdd5743d71ac662885d3c7bfc Mon Sep 17 00:00:00 2001 From: Prashanth Prakash Date: Wed, 15 Nov 2017 10:11:50 -0700 Subject: ARM64 / cpuidle: Use new cpuidle macro for entering retention state CPU_PM_CPU_IDLE_ENTER_RETENTION skips calling cpu_pm_enter() and cpu_pm_exit(). By not calling cpu_pm functions in idle entry/exit paths we can reduce the latency involved in entering and exiting the low power idle state. On ARM64 based Qualcomm server platform we measured below overhead for calling cpu_pm_enter and cpu_pm_exit for retention states. workload: stress --hdd #CPUs --hdd-bytes 32M -t 30 Average overhead of cpu_pm_enter - 1.2us Average overhead of cpu_pm_exit - 3.1us Acked-by: Sudeep Holla Signed-off-by: Prashanth Prakash Signed-off-by: Catalin Marinas --- arch/arm64/kernel/cpuidle.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'arch/arm64/kernel/cpuidle.c') diff --git a/arch/arm64/kernel/cpuidle.c b/arch/arm64/kernel/cpuidle.c index fd691087dc9a..f2d13810daa8 100644 --- a/arch/arm64/kernel/cpuidle.c +++ b/arch/arm64/kernel/cpuidle.c @@ -47,6 +47,8 @@ int arm_cpuidle_suspend(int index) #include +#define ARM64_LPI_IS_RETENTION_STATE(arch_flags) (!(arch_flags)) + int acpi_processor_ffh_lpi_probe(unsigned int cpu) { return arm_cpuidle_init(cpu); @@ -54,6 +56,10 @@ int acpi_processor_ffh_lpi_probe(unsigned int cpu) int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi) { - return CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, lpi->index); + if (ARM64_LPI_IS_RETENTION_STATE(lpi->arch_flags)) + return CPU_PM_CPU_IDLE_ENTER_RETENTION(arm_cpuidle_suspend, + lpi->index); + else + return CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, lpi->index); } #endif -- cgit v1.2.3