From patchwork Wed Sep 2 03:25:23 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 513277 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 71D751401F0 for ; Wed, 2 Sep 2015 13:29:02 +1000 (AEST) Received: from localhost ([::1]:32966 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZWyjM-000465-Hx for incoming@patchwork.ozlabs.org; Tue, 01 Sep 2015 23:29:00 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43299) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZWygE-0007Q6-J5 for qemu-devel@nongnu.org; Tue, 01 Sep 2015 23:25:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZWygB-0006nG-16 for qemu-devel@nongnu.org; Tue, 01 Sep 2015 23:25:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57214) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZWygA-0006nB-R4 for qemu-devel@nongnu.org; Tue, 01 Sep 2015 23:25:42 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (Postfix) with ESMTPS id 862A1C0EE053; Wed, 2 Sep 2015 03:25:42 +0000 (UTC) Received: from jason-ThinkPad-T430s.nay.redhat.com (dhcp-14-122.nay.redhat.com [10.66.14.122]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t823PQfm024102; Tue, 1 Sep 2015 23:25:40 -0400 From: Jason Wang To: qemu-devel@nongnu.org Date: Wed, 2 Sep 2015 11:25:23 +0800 Message-Id: <1441164325-14417-7-git-send-email-jasowang@redhat.com> In-Reply-To: <1441164325-14417-1-git-send-email-jasowang@redhat.com> References: <1441164325-14417-1-git-send-email-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: cornelia.huck@de.ibm.com, Jason Wang , mst@redhat.com Subject: [Qemu-devel] [PATCH V2 6/8] virtio-pci: use wildcard mmio eventfd for 1.0 notification cap X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org We use data match eventfd for 1.0 notification currently. This could be slow since software decoding is needed for mmio exit. To speed this up, we can switch to use wild card mmio eventfd for 1.0 notification since we can examine the queue index directly from the writing address. KVM kernel module can utilize this by registering it to fast mmio bus which could be as fast as pio on ept capable machine. Lots of improvements were seen on a ept capable machine: Guest RX:(TCP) size/session/+throughput%/+cpu%/-+per cpu%/ 64/1/+1.6807%/[-16.2421%]/[+21.3984%]/ 64/2/+0.6091%/[-11.0187%]/[+13.0678%]/ 64/4/+0.0553%/[-5.9768%]/[+6.4155%]/ 64/8/+0.1206%/[-4.0057%]/[+4.2984%]/ 256/1/-0.0031%/[-10.1166%]/[+11.2517%]/ 256/2/-0.5058%/[-6.1656%]/+6.0317%]/ ... Guest TX:(TCP) size/session/+throughput%/+cpu%/-+per cpu%/ 64/1/[+18.9183%]/-0.2823%/[+19.2550%]/ 64/2/[+13.5714%]/[+2.2675%]/[+11.0533%]/ 64/4/[+13.1070%]/[+2.1817%]/[+10.6920%]/ 64/8/[+13.0426%]/[+2.0887%]/[+10.7299%]/ 256/1/[+36.2761%]/+6.3434%/[+28.1471%]/ ... 1024/1/[+44.8873%]/+2.0811%/[+41.9335%]/ ... 1024/4/+0.0228%/[-2.2044%]/[+2.2774%]/ ... 16384/2/+0.0127%/[-5.0346%]/[+5.3148%]/ ... 65535/1/[+0.0062%]/[-4.1183%]/[+4.3017%]/ 65535/2/+0.0004%/[-4.2311%]/[+4.4185%]/ 65535/4/+0.0107%/[-4.6106%]/[+4.8446%]/ 65535/8/-0.0090%/[-5.5178%]/[+5.8306%]/ Latency:(TCP_RR) size/session/+transaction rate%/+cpu%/-+per cpu%/ 64/1/[+6.5248%]/[-9.2882%]/[+17.4322%]/ 64/25/[+11.0854%]/[+0.8000%]/[+10.2038%]/ 64/50/[+12.1076%]/[+2.4627%]/[+9.4131%]/ 256/1/[+5.3677%]/[+10.5669%]/-4.7024%/ 256/25/[+5.6402%]/-0.8962%/[+6.5955%]/ 256/50/[+5.9685%]/[+1.7766%]/[+4.1188%]/ 4096/1/+0.2508%/[-10.4941%]/[+12.0047%]/ 4096/25/[+1.8533%]/-0.0273%/+1.8812%/ 4096/50/[+1.2156%]/-1.4134%/+2.6667%/ Notes: data with '[]' is the one whose significance is greater than 95%. Thanks Wenli Quan for the benchmarking. Cc: Michael S. Tsirkin Signed-off-by: Jason Wang --- hw/virtio/virtio-pci.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c index a96890b..2d00d06 100644 --- a/hw/virtio/virtio-pci.c +++ b/hw/virtio/virtio-pci.c @@ -286,8 +286,8 @@ static int virtio_pci_set_host_notifier_internal(VirtIOPCIProxy *proxy, } virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler); if (modern) { - memory_region_add_eventfd(modern_mr, modern_addr, 2, - true, n, notifier); + memory_region_add_eventfd(modern_mr, modern_addr, 0, + false, n, notifier); } if (legacy) { memory_region_add_eventfd(legacy_mr, legacy_addr, 2, @@ -295,8 +295,8 @@ static int virtio_pci_set_host_notifier_internal(VirtIOPCIProxy *proxy, } } else { if (modern) { - memory_region_del_eventfd(modern_mr, modern_addr, 2, - true, n, notifier); + memory_region_del_eventfd(modern_mr, modern_addr, 0, + false, n, notifier); } if (legacy) { memory_region_del_eventfd(legacy_mr, legacy_addr, 2,