On Wed, Jun 07, 2017 at 15:22:48 +0100, Alex Bennée wrote:
>
> Alex Bennée <alex.ben...@linaro.org> writes:
>
> > Richard Henderson <r...@twiddle.net> writes:
> >
> >> From: "Emilio G. Cota" <c...@braap.org>
> >>
> >> Measurements:
> >>
> >> [Baseline performance is that before applying this and the previous
> >> commit]
> >
> > Sadly this has regressed my qemu-system-aarch64 EL2 run. It was slightly
> > masked by an unrelated assertion breakage which I had to fix. However
> > with this patch my boot hangs spinning all 4 threads. Once reverted
> > things work again.
> >
> > My command line:
> >
> > timeout -k 1s --foreground 120s ./aarch64-softmmu/qemu-system-aarch64
> > -machine type=virt -display none -m 4096 -cpu cortex-a57 -serial mon:stdio
> > -netdev user,id=unet -device virtio-net-device,netdev=unet -drive
> > file=/home/alex/lsrc/qemu/images/jessie-arm64.qcow2,id=myblock,index=0,if=none
> > -device virtio-blk-device,drive=myblock -append "console=ttyAMA0
> > root=/dev/vda1 systemd.unit=benchmark.service" -kernel
> > /home/alex/lsrc/qemu/images/aarch64-current-linux-kernel-only.img -smp 4
> > -machine gic-version=3 -machine virtualization=true -name debug-threads=on
> >
> > My tree with fix and revert:
> >
> > https://github.com/stsquad/qemu/tree/debug/aarch64-hang
> >
> > I'm investigating now.
>
> Well this seems to be a case of hangs with -smp > 1 (which I guess was
> obvious seeing as the TCG threads seem to be spinning against each
> other).
Not sure the problem is in MTTCG; I cannot reproduce with -smp > 1 and
thread=single; can you? [ I get no output whatsoever when trying to boot ]
Note that you'll need to revert bde4d9205ee to get thread=foo to
work again -- see [1].
Thanks,
E.
[1] https://lists.gnu.org/archive/html/qemu-devel/2017-06/msg01980.html
