Re: [Qemu-devel] [PULL 22/26] target/aarch64: optimize indirect branches

[Alex Bennée]

Richard Henderson <address@hidden> writes:

> From: "Emilio G. Cota" <address@hidden>
>
> 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.

--
Alex Bennée