From patchwork Tue Sep 14 15:13:13 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 64716 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 312215DEBA for ; Wed, 15 Sep 2010 01:16:10 +1000 (EST) Received: from localhost ([127.0.0.1]:59363 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OvXEt-0001bY-50 for incoming@patchwork.ozlabs.org; Tue, 14 Sep 2010 11:16:07 -0400 Received: from [140.186.70.92] (port=59175 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OvXCB-0008DB-Go for qemu-devel@nongnu.org; Tue, 14 Sep 2010 11:13:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OvXC7-00089d-FQ for qemu-devel@nongnu.org; Tue, 14 Sep 2010 11:13:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:31312) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OvXC7-00089T-9E for qemu-devel@nongnu.org; Tue, 14 Sep 2010 11:13:15 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o8EFDErm005715 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 14 Sep 2010 11:13:14 -0400 Received: from s20.home (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o8EFDD1M010284; Tue, 14 Sep 2010 11:13:13 -0400 From: Alex Williamson To: qemu-devel@nongnu.org Date: Tue, 14 Sep 2010 09:13:13 -0600 Message-ID: <20100914151230.4223.79925.stgit@s20.home> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. Cc: alex.williamson@redhat.com Subject: [Qemu-devel] [PATCH] apic: Don't iterate past last used apic X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org local_apics are allocated sequentially and never removed, so we can stop any iterations that go to MAX_APICS as soon as we hit the first NULL. Looking at a small guest running a virtio-net workload with oprofile, this drops apic_get_delivery_bitmask() from #3 in the profile to down in the noise. Signed-off-by: Alex Williamson --- Post 0.13 hw/apic.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/hw/apic.c b/hw/apic.c index d686b51..c07238c 100644 --- a/hw/apic.c +++ b/hw/apic.c @@ -449,6 +449,8 @@ static int apic_find_dest(uint8_t dest) apic = local_apics[i]; if (apic && apic->id == dest) return i; + if (!apic) + break; } return -1; @@ -484,6 +486,8 @@ static void apic_get_delivery_bitmask(uint32_t *deliver_bitmask, set_bit(deliver_bitmask, i); } } + } else { + break; } } }