Re: [Qemu-discuss] Very poor compilation performance in armhf chroot vs native

[Aboul Fad]

Thank you for your reply. I am though stumped by that large of degradation
using that simple test and when I attempted to compile my actual project
(chromium) in the chroot, it was insanely slow.

Maybe this is off topic or meant for another mailing list: It seems my
approach for cross compiling using qemu-arm/chroot is wrong. I know I can
install a cross compile toolchain for arm target on the native OS and cross
compile there. Sadly, I have a chromium packaging code that checks the host
arch and based on that will or not cross-compile.

Is there a way to take advantage of a hybrid approach:  compile on the
native hardware/OS using cross compile toolchain and link in chroot using
qemu-arm-static?

Best regards!

On Thu, Sep 12, 2019 at 4:46 AM Peter Maydell <address@hidden>
wrote:

> On Wed, 11 Sep 2019 at 20:33, Aboul Fad <address@hidden> wrote:
> >
> > Hello,
> >
> > I am not entirely sure if this belongs here, if not it would be greatly
> > appreciated to redirect me to the best mailing list.
> >
> > I have setup an ARM chroot on a Xenial system, compiled and installed
> > qemu-arm-static from source v4.1.0.
> > I compiled using gcc a simple hello world on the native system (Xenial)
> and
> > the same in the ARM chroot using qemu-arm-static.
> >
> > The performance degradation is large (~15x slower) and am unsure if this
> is
> > expected because qemu-arm-static is emulating instructions in user space
> or
> > what ?
>
> Yes, emulation is slower than running on real hardware.
> (Note also that your test isn't strictly comparing like for
> like, because the two compilers are outputting different
> things. But it probably doesn't make much difference.)
>
> thanks
> -- PMM
>