From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1G6TxL-0004ml-NX for qemu-devel@nongnu.org; Fri, 28 Jul 2006 11:08:51 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1G6TxJ-0004lW-Vp for qemu-devel@nongnu.org; Fri, 28 Jul 2006 11:08:51 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1G6TxJ-0004lM-MI for qemu-devel@nongnu.org; Fri, 28 Jul 2006 11:08:49 -0400 Received: from [203.190.192.17] (helo=wasp.net.au) by monty-python.gnu.org with esmtp (Exim 4.52) id 1G6TzK-0005Wt-33 for qemu-devel@nongnu.org; Fri, 28 Jul 2006 11:10:54 -0400 Message-ID: <44CA2876.8030308@wasp.net.au> Date: Fri, 28 Jul 2006 19:08:38 +0400 From: Brad Campbell MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] /dev/rtc Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org G'day all, Been playing with multiple vm's on linux and hacking around my suspend/resume dropped interrupt issues. I just noticed the /dev/rtc interface appears to be very single use oriented. If I run multiple vm's simultaneously on the same machine, the 1st one picks up the interrupt driven timer and the rest must revert to userspace based timers. open("/dev/rtc", O_RDONLY|O_LARGEFILE) = -1 EBUSY (Device or resource busy) Not having investigated this much further as I'm testing on a fairly low powered device, but I wonder how this impacts server applications where we desire to run several qemu instances concurrently. (I have already played with dropping the timer interrupt rate back from 1024 to 256 and it really does not appear to impact my linux guests, but it makes my windows guests audio unusable. Still experimenting with that) Just fishing for comments really.. wondering about some form of shared interrupt timing device to allow multiple instances to run with full timer resolution or if it really even matters. Brad -- "Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so." -- Douglas Adams