From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerd von Egidy Subject: Re: disappointing speed with virtio_blk Date: Thu, 17 Apr 2008 01:05:50 +0200 Message-ID: <200804170105.50963.lists@egidy.de> References: <200804132304.44950.lists@egidy.de> <20080414002902.GA4546@dmt> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti To: kvm-devel@lists.sourceforge.net Return-path: In-Reply-To: <20080414002902.GA4546@dmt> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org Hi Marcelo, > virtio-blk is doing synchronous IO which blocks the guest CPU. > > This is especially bad for write intensive loads where the guest > will hang in the host write throttling logic. > > In the meantime please try the following patch: > > http://www.mail-archive.com/kvm-devel@lists.sourceforge.net/msg14732.html Thank you for this hint. I tried it this evening with kvm 66 - which should include your patch, right? The result, at least with bonnie++, is nearly the same. I looked at the patch for the guest kernel you sent with this patch but looking at the discussion it did not work. Kind regards, Gerd -- Address (better: trap) for people I really don't want to get mail from: james@cactusamerica.com ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone