From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:57999) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sf6Dr-0004xc-NA for qemu-devel@nongnu.org; Thu, 14 Jun 2012 05:20:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Sf6Dl-0003Fj-Cn for qemu-devel@nongnu.org; Thu, 14 Jun 2012 05:20:11 -0400 Received: from mail-we0-f173.google.com ([74.125.82.173]:61643) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sf6Dl-0003Cc-4M for qemu-devel@nongnu.org; Thu, 14 Jun 2012 05:20:05 -0400 Received: by werf3 with SMTP id f3so1254834wer.4 for ; Thu, 14 Jun 2012 02:20:03 -0700 (PDT) Sender: Paolo Bonzini Message-ID: <4FD9ACBC.2090304@redhat.com> Date: Thu, 14 Jun 2012 11:19:56 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Broken Microblaze timer List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Crosthwaite Cc: "Edgar E. Iglesias" , Anthony Liguori , "qemu-devel@nongnu.org Developers" , Paul Brook Il 14/06/2012 04:29, Peter Crosthwaite ha scritto: > Obviously this sucks as a patch, but without this hack, the system > freezes on boot. I managed to ascertain that its coming from the > ptimer used by the system timer (hw/xilinx_timer.c). The CPU is either > halted and never resumes, or the timer is flooding with halt requests > and the CPU never gets another look in. > > The question is, is this a failure in ptimer, xilinx_timer or the > async framework? Can ptimer be misused such that the CPU is locked up? Yes, this looks like the ptimer is flooding the iothread so that the CPU does not get an occasion to run. Perhaps you want to limit the rate of the hw/xilinx_timer.c to something like 1000 Hz or something like that. Paolo