From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35040) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZSiH5-0003KA-Um for qemu-devel@nongnu.org; Fri, 21 Aug 2015 05:06:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZSiH4-0002Hz-U4 for qemu-devel@nongnu.org; Fri, 21 Aug 2015 05:06:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42568) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZSiH4-0002Hh-Nm for qemu-devel@nongnu.org; Fri, 21 Aug 2015 05:06:10 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id 73B6A71 for ; Fri, 21 Aug 2015 09:06:10 +0000 (UTC) From: Jason Wang Date: Fri, 21 Aug 2015 17:05:48 +0800 Message-Id: <1440147950-1178-5-git-send-email-jasowang@redhat.com> In-Reply-To: <1440147950-1178-1-git-send-email-jasowang@redhat.com> References: <1440147950-1178-1-git-send-email-jasowang@redhat.com> Subject: [Qemu-devel] [PATCH 4/6] virtio-pci: use wildcard mmio eventfd for 1.0 notification cap List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, mst@redhat.com Cc: Jason Wang 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 d785623..fbd1f1f 100644 --- a/hw/virtio/virtio-pci.c +++ b/hw/virtio/virtio-pci.c @@ -226,8 +226,8 @@ 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, @@ -235,8 +235,8 @@ 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, -- 2.1.4