Re: [Qemu-devel] Call for testing QEMU aarch64-linux-user emulation

[Janne Grunau]

Hi,

On 2014-02-17 13:40:00 +0000, Alex Bennée wrote:
> 
> After a solid few months of work the QEMU master branch [1] has now reached
> instruction feature parity with the suse-1.6 [6] tree that a lot of people
> have been using to build various aarch64 binaries. In addition to the
> SUSE work we have fixed numerous edge cases and finished off classes of
> instructions. All instructions have been verified with Peter's RISU
> random instruction testing tool. I have also built and run many
> packages as well as built gcc and passed most of the aarch64 specific tests.
> 
> I've tested against the following aarch64 rootfs:
>     * SUSE [2]
>     * Debian [3]
>     * Ubuntu Saucy [4]

I'm running Libav's test suite 
(https://fate.libav.org/?arch=aarch64&comment=qemu)
using a Gentoo crossdev sysroot.

> In my tree the remaining insns that the GCC aarch64 tests need to
> implement are:
>     FRECPE
>     FRECPX
>     CLS (2 misc variant)
>     CLZ (2 misc variant)
>     FSQRT
>     FRINTZ
>     FCVTZS
> 
> Which I'm currently working though now. However for most build tasks I
> expect the instructions in master [1] will be enough.

Qemu master is enough to pass the tests with libav built with gcc 4.8.2,
clang 3.3 and 3.4 (clang 3.4 build only with -O1, it fails otherwise).

> Feedback I'm interested in
> ==========================
> 
> * Any instruction failure (please include the log line with the
>   unsupported message)

Neon support is not complete enough to run the hand written neon
assembler optimizations in libav. Currently failing on narrowing shifts.

> * Any aarch64 specific failures (i.e. not generic QEMU threading flakeiness).

Just as a note, qemu-arm64 from the suse tree didn't show any threading
issues with the libav test suite while qemu-aarch64 from master failed
with a probability of ~10% running the same binary.
 
> Many thanks to the SUSE guys for getting the aarch64 train rolling. I
> hope your happy with the final result ;-)

I'm happy, qemu master runs the libav test suite around 30% faster.
Thanks to everyone involved.

Janne