From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41147) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dG7k0-0000MK-TA for qemu-devel@nongnu.org; Wed, 31 May 2017 13:49:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dG7jw-0003yE-1u for qemu-devel@nongnu.org; Wed, 31 May 2017 13:49:04 -0400 Received: from mail-wm0-x233.google.com ([2a00:1450:400c:c09::233]:37253) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1dG7jv-0003xR-RV for qemu-devel@nongnu.org; Wed, 31 May 2017 13:48:59 -0400 Received: by mail-wm0-x233.google.com with SMTP id d127so29314786wmf.0 for ; Wed, 31 May 2017 10:48:58 -0700 (PDT) Message-ID: <1496252935.14809.59.camel@gmail.com> From: Mihai =?UTF-8?Q?Don=C8=9Bu?= Date: Wed, 31 May 2017 20:48:55 +0300 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] Doubts about Kvm architecture List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?ISO-8859-1?Q?Maur=EDcio?= Almeida Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org On Wed, 2017-05-31 at 14:09 -0300, Maurício Almeida wrote: > My name is Maurício, we are making a study about Kvm Paravirtualized > and Full virtualized at our University, we are from University Federal > of Santa Maria. > Can you give us some papers about how the Kvm or Qemu executes the I/O > Network with one emulated Device? > > We executed some tests using Virtio Driver and e1000 emulated driver, > the network output of Virtio is normal and use four of the four > Machine Cpu's, but the output of e1000 Emulated driver was too low > about Virtio and It onlyused one of the four machine cpu's during the > network test execution. > The Traffic of Virtio was 956 MB/s while e1000 Emulated Driver was 192 > MB/s, both using Packet size of 1518 Bytes. > > Why when it used e1000 Emulated Driver the traffic was to low and use > only one Cpu all the time? > Do Qemu or Kvm Guest need some specific configuration to use all CPU's? > > Do you have any paper where we can find in details if Qemu is limited > to use one CPU when use Network Emulated Driver? A cursory look over the qemu e1000 driver would suggest that it does not support multithreading. virtio largely bypasses the qemu hw machinery. -- Mihai Donțu