From mboxrd@z Thu Jan 1 00:00:00 1970 From: Prashanth Prakash Subject: [PATCH v3 2/2] ARM64 / cpuidle: Use new cpuidle macro for entering retention state Date: Wed, 15 Nov 2017 10:11:50 -0700 Message-ID: <1510765910-23739-3-git-send-email-pprakash@codeaurora.org> References: <1510765910-23739-1-git-send-email-pprakash@codeaurora.org> Return-path: Received: from smtp.codeaurora.org ([198.145.29.96]:47708 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933358AbdKORMD (ORCPT ); Wed, 15 Nov 2017 12:12:03 -0500 In-Reply-To: <1510765910-23739-1-git-send-email-pprakash@codeaurora.org> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: sudeep.holla@arm.com, rjw@rjwysocki.net, daniel.lezcano@linaro.org, will.deacon@arm.com, catalin.marinas@arm.com, Prashanth Prakash 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 Signed-off-by: Prashanth Prakash --- arch/arm64/kernel/cpuidle.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/cpuidle.c b/arch/arm64/kernel/cpuidle.c index fd69108..f2d1381 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 -- Qualcomm Datacenter Technologies on behalf of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.