From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH] qemu-kvm: Consolidate kvm_eat_signals Date: Mon, 12 May 2008 10:11:54 -0500 Message-ID: <48285E3A.1080806@codemonkey.ws> References: <482820DC.6030509@web.de> <48282B16.7050006@qumranet.com> <48282D13.9060903@web.de> <48283071.5030600@qumranet.com> <482854D2.50100@codemonkey.ws> <48285754.5080600@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel , Jan Kiszka To: Avi Kivity Return-path: In-Reply-To: <48285754.5080600@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: >> Now the VCPU threads never select so the whole loop can be simplified >> to a single sigtimedwait() that always blocks. >> >> In reality, I don't think sigtimedwait() is really needed/useful for >> VCPUs anymore. We only use it to catch SIG_IPI and we only use >> SIG_IPI to break out of sleeping. I don't see any reason why we >> couldn't switch over to using a file descriptor for notification (or >> a pthread condition). > > How would you stop a vcpu running in guest mode? Yeah, I forgot about that. >> In the very least, we could just select() on nothing and allow >> SIG_IPI to break us out of the select. > > sigtimedwait() (or just sigwait, now) doesn't require the signal to be > delivered, so it's faster. Yeah, sigtimedwait() is probably the right thing to do since we have to use a signal for IPI. Regards, Anthony Liguori > If there's nothing to select, why call select()? > ------------------------------------------------------------------------- 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