From patchwork Mon May 11 21:06:47 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Len Brown X-Patchwork-Id: 6384121 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 5ADEABEEE1 for ; Mon, 11 May 2015 21:07:26 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 4BD8720C8D for ; Mon, 11 May 2015 21:07:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3F33D20C88 for ; Mon, 11 May 2015 21:07:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753773AbbEKVHW (ORCPT ); Mon, 11 May 2015 17:07:22 -0400 Received: from mail-qg0-f54.google.com ([209.85.192.54]:36353 "EHLO mail-qg0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932368AbbEKVG5 (ORCPT ); Mon, 11 May 2015 17:06:57 -0400 Received: by qgeb100 with SMTP id b100so74789556qge.3; Mon, 11 May 2015 14:06:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=Atbl5TXxvXWhBrUWGgCcZgDTyAwszCxcCiFhf9UAy70=; b=kvpgpXeX9sioX5cQPeR6zaheNbsyNefHeHFGCVqWOH+2Us8B57ZqAS+vwCsJiZ46pV QvDC2jTCVlfN3VB+8ajCrEyX1XF9UzDTJo43AC7/ia4tl12NY5RDgWPakymmPM/c7s8H ryV0yLITfENmkvo7qChpGAh1XZswmlCyS3nx8bpMHjljBCUoxppWrzTd0dB2/E9xj+Sw nUNCagc19RvmpUS5RKfr/g+i8i1AkvfUJo4uQfIHKl0QbbBi5S77bwpF8WQVcS855qcX LQPZf5kum7iHgrKlh4oCx1NabkqCNvP+iIfpZdMUcShrhtIFfDkyABts/Ccz7zi6hRYg lUOw== X-Received: by 10.140.106.202 with SMTP id e68mr15484575qgf.42.1431378417173; Mon, 11 May 2015 14:06:57 -0700 (PDT) Received: from z87.localdomain (pool-100-0-21-20.bstnma.fios.verizon.net. [100.0.21.20]) by mx.google.com with ESMTPSA id q105sm11635451qgq.11.2015.05.11.14.06.55 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 11 May 2015 14:06:56 -0700 (PDT) From: Len Brown To: x86@kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Len Brown Subject: [PATCH 1/2] x86: Add cmdline "cpu_init_udelay=N" to specify cpu_up() delay Date: Mon, 11 May 2015 17:06:47 -0400 Message-Id: <98c0dd8b8d5516124418cf4c1bf6c2e3630d7d8b.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> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID,T_RP_MATCHES_RCVD,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Len Brown No change to default behavior. Replace the hard-coded mdelay(10) in cpu_up() with a variable udelay, that is set to a defined default -- rather than a magic number. Add a boot-time override, "cpu_init_udelay=N" Signed-off-by: Len Brown --- Documentation/kernel-parameters.txt | 6 ++++++ arch/x86/kernel/smpboot.c | 23 ++++++++++++++++++++++- arch/x86/kernel/smpboot.c.rej | 11 +++++++++++ 3 files changed, 39 insertions(+), 1 deletion(-) create mode 100644 arch/x86/kernel/smpboot.c.rej diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 61ab162..a320a41 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -746,6 +746,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. cpuidle.off=1 [CPU_IDLE] disable the cpuidle sub-system + cpu_init_udelay=N + [X86] Delay for N microsec between assert and de-assert + of APIC INIT to start processors. This delay occurs + on every CPU online, such as boot, and resume from suspend. + Default: 10000 + cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver Format: ,,,[,] diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 51203f6..0629a8e 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -514,6 +514,27 @@ void __inquire_remote_apic(int apicid) } /* + * The Multiprocessor Specification 1.4 (1997) example code suggests + * that there should be a 10ms delay between the BSP asserting INIT + * and de-asserting INIT, when starting a remote processor. + * But that slows boot and resume on modern processors, which include + * many cores and don't require that delay. + * + * Cmdline "init_cpu_udelay=" is available to over-ride this delay. + */ +#define UDELAY_10MS_DEFAULT 10000 + +static unsigned int init_udelay = UDELAY_10MS_DEFAULT; + +static int __init cpu_init_udelay(char *str) +{ + get_option(&str, &init_udelay); + + return 0; +} +early_param("cpu_init_udelay", cpu_init_udelay); + +/* * 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 * won't ... remember to clear down the APIC, etc later. @@ -584,7 +605,7 @@ wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip) pr_debug("Waiting for send to finish...\n"); send_status = safe_apic_wait_icr_idle(); - mdelay(10); + mdelay(init_udelay); pr_debug("Deasserting INIT\n"); diff --git a/arch/x86/kernel/smpboot.c.rej b/arch/x86/kernel/smpboot.c.rej new file mode 100644 index 0000000..ccf0bd0 --- /dev/null +++ b/arch/x86/kernel/smpboot.c.rej @@ -0,0 +1,11 @@ +--- arch/x86/kernel/smpboot.c ++++ arch/x86/kernel/smpboot.c +@@ -607,7 +628,7 @@ wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip) + pr_debug("Waiting for send to finish...\n"); + send_status = safe_apic_wait_icr_idle(); + +- mdelay(10); ++ udelay(init_udelay); + + pr_debug("Deasserting INIT\n"); +