From patchwork Tue Dec 6 06:43:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Li RongQing X-Patchwork-Id: 631482 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6A3AC352A1 for ; Tue, 6 Dec 2022 07:02:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230348AbiLFHCJ (ORCPT ); Tue, 6 Dec 2022 02:02:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45488 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231527AbiLFHCJ (ORCPT ); Tue, 6 Dec 2022 02:02:09 -0500 X-Greylist: delayed 600 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 05 Dec 2022 23:02:06 PST Received: from mx417.baidu.com (mx411.baidu.com [124.64.200.154]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id CDE8E23393 for ; Mon, 5 Dec 2022 23:02:06 -0800 (PST) Received: from bjhw-sys-rpm015653cc5.bjhw.baidu.com (bjhw-sys-rpm015653cc5.bjhw.baidu.com [10.227.53.39]) by mx417.baidu.com (Postfix) with ESMTP id B68D219B80406; Tue, 6 Dec 2022 14:43:18 +0800 (CST) Received: from localhost (localhost [127.0.0.1]) by bjhw-sys-rpm015653cc5.bjhw.baidu.com (Postfix) with ESMTP id B00A7D9932; Tue, 6 Dec 2022 14:43:18 +0800 (CST) From: lirongqing@baidu.com To: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, rafael@kernel.org, daniel.lezcano@linaro.org, peterz@infradead.org, akpm@linux-foundation.org, tony.luck@intel.com, jpoimboe@kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Subject: [PATCH] cpuidle-haltpoll: Disable kvm guest polling when mwait_idle is used Date: Tue, 6 Dec 2022 14:43:18 +0800 Message-Id: <1670308998-12313-1-git-send-email-lirongqing@baidu.com> X-Mailer: git-send-email 1.7.1 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Li RongQing when KVM guest has mwait and mwait_idle is used as default idle function, Loading cpuidle-haltpoll will make idle function back to default_idle which is using HLT, As the commit aebef63cf7ff ("x86: Remove vendor checks from prefer_mwait_c1_over_halt") explains that mwait is preferred so disable kvm guest polling in this conditions to improve performance, like sockperf localhost test shows that latency is reduced by about 20% Signed-off-by: Li RongQing --- arch/x86/include/asm/processor.h | 2 ++ arch/x86/kernel/process.c | 6 ++++++ drivers/cpuidle/cpuidle-haltpoll.c | 4 ++++ 3 files changed, 12 insertions(+) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 67c9d73..159ef33 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -862,4 +862,6 @@ bool arch_is_platform_page(u64 paddr); #define arch_is_platform_page arch_is_platform_page #endif +bool is_mwait_idle(void); + #endif /* _ASM_X86_PROCESSOR_H */ diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index c21b734..330972c 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -896,6 +896,12 @@ void select_idle_routine(const struct cpuinfo_x86 *c) x86_idle = default_idle; } +bool is_mwait_idle(void) +{ + return x86_idle == mwait_idle; +} +EXPORT_SYMBOL_GPL(is_mwait_idle); + void amd_e400_c1e_apic_setup(void) { if (boot_cpu_has_bug(X86_BUG_AMD_APIC_C1E)) { diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c index 3a39a7f..8cf1ddf 100644 --- a/drivers/cpuidle/cpuidle-haltpoll.c +++ b/drivers/cpuidle/cpuidle-haltpoll.c @@ -17,6 +17,7 @@ #include #include #include +#include static bool force __read_mostly; module_param(force, bool, 0444); @@ -111,6 +112,9 @@ static int __init haltpoll_init(void) if (!kvm_para_available() || !haltpoll_want()) return -ENODEV; + if (is_mwait_idle()) + return -ENODEV; + cpuidle_poll_state_init(drv); ret = cpuidle_register_driver(drv);