From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=48274 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OIhCT-0007cA-Lk for qemu-devel@nongnu.org; Sun, 30 May 2010 08:01:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OIhCS-00023G-Fy for qemu-devel@nongnu.org; Sun, 30 May 2010 08:01:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:17962) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OIhCS-000237-62 for qemu-devel@nongnu.org; Sun, 30 May 2010 08:01:04 -0400 Message-ID: <4C025371.7060101@redhat.com> Date: Sun, 30 May 2010 15:00:49 +0300 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [Qemu-devel] Re: [RFT][PATCH 07/15] qemu_irq: Add IRQ handlers with delivery feedback References: <4BFD8010.3010001@web.de> <201005270026.34119.paul@codesourcery.com> <4BFEBA66.6030804@web.de> <4BFEC322.3030207@web.de> <4BFEEFE1.2050602@web.de> In-Reply-To: <4BFEEFE1.2050602@web.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: Blue Swirl , qemu-devel@nongnu.org, Paul Brook , Juan Quintela On 05/28/2010 01:19 AM, Jan Kiszka wrote: > > Still, this does not answer: > > - How do you want to detect lost timer ticks? > > Your (and Gleb's) approach: during injection An alternative: during guest ack The normal pattern is inj/ack/inj/ack; if we see inj/inj/inj we know the guest isn't keeping up. > - What subsystem(s) keeps track of the backlog? > Clearly, the clock chip (hpet/rtc/pit). With the alternative approach, the clock emulation requests that acks be reported via a qemu_irq interface. > - And depending on the above: How to detect at all that a specific IRQ > is a timer tick? > Clearly, a blocker unless the clock is responsible for timekeeping. -- error compiling committee.c: too many arguments to function