From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from numascale.com ([213.162.240.84]:57480 "EHLO numascale.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752224AbaKDIbM (ORCPT ); Tue, 4 Nov 2014 03:31:12 -0500 From: Daniel J Blueman To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Bjorn Helgaas Cc: Daniel J Blueman , x86@kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, Steffen Persvold Subject: [PATCH v4 2/4] Numachip: Elide self-IPI ICR polling Date: Tue, 4 Nov 2014 16:29:42 +0800 Message-Id: <1415089784-28779-2-git-send-email-daniel@numascale.com> In-Reply-To: <1415089784-28779-1-git-send-email-daniel@numascale.com> References: <1415089784-28779-1-git-send-email-daniel@numascale.com> Sender: linux-pci-owner@vger.kernel.org List-ID: The default self-IPI path polls the ICR to delay sending the IPI until there is no IPI in progress. This is redundant on x86-86 APICs, since IPIs are queued. See the AMD64 Architecture Programmer's Manual, vol 2, p525. Signed-off-by: Daniel J Blueman --- apic_numachip.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/apic/apic_numachip.c b/arch/x86/kernel/apic/apic_numachip.c index 81d70ba..bd083c0 100644 --- a/arch/x86/kernel/apic/apic_numachip.c +++ b/arch/x86/kernel/apic/apic_numachip.c @@ -145,7 +145,7 @@ static void numachip_send_IPI_all(int vector) static void numachip_send_IPI_self(int vector) { - __default_send_IPI_shortcut(APIC_DEST_SELF, vector, APIC_DEST_PHYSICAL); + apic_write(APIC_SELF_IPI, vector); } static int __init numachip_probe(void) -- 1.9.1