From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=53836 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Pelvf-0006nA-1I for qemu-devel@nongnu.org; Mon, 17 Jan 2011 05:03:15 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Pelve-0002qO-3k for qemu-devel@nongnu.org; Mon, 17 Jan 2011 05:03:14 -0500 Received: from mail-fx0-f45.google.com ([209.85.161.45]:45367) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Pelvd-0002qK-V7 for qemu-devel@nongnu.org; Mon, 17 Jan 2011 05:03:14 -0500 Received: by fxm12 with SMTP id 12so6015913fxm.4 for ; Mon, 17 Jan 2011 02:03:12 -0800 (PST) Date: Mon, 17 Jan 2011 11:03:08 +0100 From: "Edgar E. Iglesias" Message-ID: <20110117100308.GA12308@edde.se.axis.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: [Qemu-devel] MIPS, io-thread, icount and wfi List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Hi, I'm running an io-thread enabled qemu-system-mipsel with icount. When the guest (linux) goes to sleep through the wait insn (waiting to be woken up by future timer interrupts), the thing deadlocks. IIUC, this is because vm timers are driven by icount, but the CPU is halted so icount makes no progress and time stands still. I've locally disabled vcpu halting when icount is enabled, that works around my problem but of course makes qemu consume 100% host cpu. I don't know why I only see this problem with io-thread builds? Could be related timing and luck. Would be interesting to know if someone has any info on how this was intended to work (if it was)? And if there are ideas for better workarounds or fixes that don't disable vcpu halting entirely. Cheers