Re: [Qemu-devel] [RFC 00/10] MultiThread TCG.

[Frederic Konrad <fred.konrad@greensocs.com>]

Hi Emilio,

On 27/04/2015 19:06, Emilio G. Cota wrote:
> Hi Fred,
>
> On Wed, Apr 22, 2015 at 14:26:14 +0200, Frederic Konrad wrote:
>> git clone git@git.greensocs.com:fkonrad/mttcg.git -b multi_tcg_v4
> I've tried to run buildroot's vexpress-a9 with this, but unfortunately
> it gets stuck before showing much progress towards boot:
> [ messages in brackets are mine ]
>
> $ time arm-softmmu/qemu-system-arm -M vexpress-a9 -kernel img/arm/zImage \
> 	-drive file=img/arm/rootfs.ext2,if=sd \
> 	-append "console=ttyAMA0,115200 root=/dev/mmcblk0" -net nic,model=lan9118 \
> 	-net user -nographic -smp 1
>
> WARNING: Image format was not specified for 'img/arm/rootfs.ext2' and probing guessed raw.
>           Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted.
>           Specify the 'raw' format explicitly to remove the restrictions.
> tlb_flush: CPU 0                        [ this 11 times more ]
> audio: Could not init `oss' audio driver
> tlb_flush: CPU 0                        [ and this 31 times ]
> [ then here it stops printing, and one thread takes 100% CPU ]
>
> Note that I'm running with -smp 1. My guess is that the iothread
> is starved, since patch 472f4003 "Drop global lock during TCG code execution"
> removes from the iothread the ability to kick CPU threads.
>
> Thanks,
>
> 		Emilio
>
Does this patch really removes the iothread the ability to kick CPU threads?
Can you check where it's blocked?

Thanks,
Fred