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Sender: Paolo Bonzini <paolo.bonzini@gmail.com>
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Date: Wed, 10 Apr 2013 09:43:19 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] latest master: major slowdown (something spinning?)
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To: "Michael R. Hines" <mrhines@linux.vnet.ibm.com>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>

Il 09/04/2013 19:43, Michael R. Hines ha scritto:
> *Here's the commit that causes the problem:*
> 
> $ git checkout d185c094b404b4ff392b77d1244c0233da7d53bd
> qemu-char: eliminate busy waiting on can_read returning zero

Can you stil reproduce it after

commit 1e885b25275fb6763eb947b1e53b2d6911b967a8
Author: Paolo Bonzini <pbonzini@redhat.com>
Date:   Mon Apr 8 15:03:15 2013 +0200

    qemu-char: really fix behavior on can_read = 0

?

Paolo

> *Symptoms:*
> 
> When the VM boots everything crawls and the host CPU is at 100%,
> messages are printing extremely slowly on the VM console
> and the VM is not making any boot progress......... printing kernel
> messages once a second or so.......
> 
> Something in QEMU appears to be spinning.
> 
> Here's my command line:
> 
> qemu-system-x86_64 -enable-kvm -m 2048 -smp
> 2,sockets=1,cores=1,threads=1 -nodefconfig -rtc base=utc -no-shutdown
> disk.img -serial pty -monitor unix:/tmp/devguest,server,nowait -netdev
> type=tap,vhost=on,id=hostnet0,script=kvmifup.sh,downscript=kvmifdown.sh
> -device virtio-net-pci,netdev=hostnet0,mac=12:34:36:00:00:02 -usb
> -device usb-tablet,id=input0  -device
> virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5
> 
> - Michael Hines