From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755977Ab1HEOJE (ORCPT ); Fri, 5 Aug 2011 10:09:04 -0400 Received: from relay3.sgi.com ([192.48.152.1]:58266 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751670Ab1HEOJC (ORCPT ); Fri, 5 Aug 2011 10:09:02 -0400 Date: Fri, 5 Aug 2011 09:09:00 -0500 From: Jack Steiner To: mingo@elte.hu, tglx@linutronix.de Cc: linux-kernel@vger.kernel.org Subject: [PATCH] x86, UV: Remove UV delay in starting slave cpus Message-ID: <20110805140900.GA6774@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Delete the 10 msec delay between the INIT and SIPI when starting slave cpus. I can find no requirement for this delay. BIOS also has similar code sequences without the delay. Removing the delay reduces boot time by 40 sec. Every bit helps. Signed-off-by: Jack Steiner --- arch/x86/kernel/apic/x2apic_uv_x.c | 1 - 1 file changed, 1 deletion(-) Index: linux/arch/x86/kernel/apic/x2apic_uv_x.c =================================================================== --- linux.orig/arch/x86/kernel/apic/x2apic_uv_x.c 2011-08-05 08:22:42.511980932 -0500 +++ linux/arch/x86/kernel/apic/x2apic_uv_x.c 2011-08-05 08:23:27.488613896 -0500 @@ -207,7 +207,6 @@ static int __cpuinit uv_wakeup_secondary ((start_rip << UVH_IPI_INT_VECTOR_SHFT) >> 12) | APIC_DM_INIT; uv_write_global_mmr64(pnode, UVH_IPI_INT, val); - mdelay(10); val = (1UL << UVH_IPI_INT_SEND_SHFT) | (phys_apicid << UVH_IPI_INT_APIC_ID_SHFT) |