From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [patch 2/2] QEMU: decrease console "refresh rate" with -nographic Date: Tue, 15 Apr 2008 08:40:09 -0500 Message-ID: <4804B039.8010801@us.ibm.com> References: <20080411183852.150819622@localhost.localdomain> <20080411184851.559593822@localhost.localdomain> <4802352A.4010105@flac.kalibalik.dk> <20080414150255.GA11640@dmt> <48038526.3090702@qumranet.com> <20080414172446.GA27224@dmt> <4803A303.8040702@us.ibm.com> <48043F8E.1040406@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net, Marcelo Tosatti To: Avi Kivity Return-path: In-Reply-To: <48043F8E.1040406@qumranet.com> 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 Avi Kivity wrote: > Anthony Liguori wrote: >> >> BTW, when we set O_ASYNC on the tap fd, we're eliminating >> O_NONBLOCK. This means that we have to poll loop select() when >> readv()'ing packets instead of just reading until hitting AGAIN. >> This means at least an extra syscall per packet. > > I didn't know that O_ASYNC and O_NONBLOCK were mutually exclusive. > Can you point me at the relevant documentation? I don't know that they are, but we're doing an: fcntl(fd, F_SETFL, O_ASYNC); F_SETFL is not additive so the previous O_NONBLOCK gets dropped. Regards, Anthony Liguori ------------------------------------------------------------------------- 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