From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932494AbbEKVHF (ORCPT ); Mon, 11 May 2015 17:07:05 -0400 Received: from mail-qg0-f54.google.com ([209.85.192.54]:36366 "EHLO mail-qg0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932276AbbEKVG7 (ORCPT ); Mon, 11 May 2015 17:06:59 -0400 From: Len Brown To: x86@kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Len Brown Subject: [PATCH 2/2] x86: remove 10ms delay from cpu_up() on modern processors Date: Mon, 11 May 2015 17:06:48 -0400 Message-Id: <7d41789ab33d6d9cd2b69a8933e0afe7322596eb.1431378048.git.len.brown@intel.com> X-Mailer: git-send-email 2.4.0.rc1 In-Reply-To: <1431378408-5840-1-git-send-email-lenb@kernel.org> References: <1431378408-5840-1-git-send-email-lenb@kernel.org> In-Reply-To: <98c0dd8b8d5516124418cf4c1bf6c2e3630d7d8b.1431378048.git.len.brown@intel.com> References: <98c0dd8b8d5516124418cf4c1bf6c2e3630d7d8b.1431378048.git.len.brown@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Len Brown Modern processor familes do not require the 10ms delay in cpu_up() to de-assert INIT. This speeds up boot and resume by 10ms per (application) processor. Signed-off-by: Len Brown --- arch/x86/kernel/smpboot.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 0629a8e..85bd6aa 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -521,6 +521,7 @@ void __inquire_remote_apic(int apicid) * many cores and don't require that delay. * * Cmdline "init_cpu_udelay=" is available to over-ride this delay. + * Modern processor families are quirked to remove the delay entirely. */ #define UDELAY_10MS_DEFAULT 10000 @@ -534,6 +535,18 @@ static int __init cpu_init_udelay(char *str) } early_param("cpu_init_udelay", cpu_init_udelay); +static void __init smp_quirk_init_udelay(void) +{ + /* if cmdline changed it from default, leave it alone */ + if (init_udelay != UDELAY_10MS_DEFAULT) + return; + + /* if modern processor, use no delay */ + if (((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 6)) || + ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && (boot_cpu_data.x86 >= 0xF))) + init_udelay = 0; +} + /* * Poke the other CPU in the eye via NMI to wake it up. Remember that the normal * INIT, INIT, STARTUP sequence will reset the chip hard for us, and this @@ -1210,6 +1223,8 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus) uv_system_init(); set_mtrr_aps_delayed_init(); + + smp_quirk_init_udelay(); } void arch_enable_nonboot_cpus_begin(void) -- 2.4.0.rc1