[Qemu-devel] Re: KVM: High CPU load with audio enabled

[Jan Kiszka <jan.kiszka@web.de>]

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Am 09.11.2010 00:48, Michael Tokarev wrote:
> 08.11.2010 15:40, Stefan Pietsch wrote:
>> Hi,
>>
>> I'm running a Windows XP guest in KVM. After enabling the audio support
>> (-soundhw es1370) the CPU load of the KVM process in the host system
>> goes up to 100%.
>>
>> Tested with: qemu-kvm-0.13.0 Debian 0.13.0+dfsg-1
>>
>> KVM start command: kvm -m 512 -hda xp.img -soundhw es1370
>>
>> Did you experience similar problems?
> 
> Yes, sound in 0.13 appears to be broken.  It is looping in
> select/read loop forever, read returns EAGAIN and select
> says the filedescriptor is ready.

Try to set QEMU_AUDIO_DAC_TRY_POLL=0 for the environment of the qemu
process. That's long required to get sound out of the Musicpal emulation
as well (malc, you may recall this). It even got worse with current
qemu.git: previously, the sounds was just quirky. Now the system is
booting way slower in polling mode and is partially not reactive anymore.

Jan



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