Re: [Qemu-devel] Debian 7.8.0 SPARC64 on qemu - anything i can do to speedup the emulation?

[Artyom Tarasenko]

On Tue, Jul 28, 2015 at 9:52 AM, Dennis Luehring <address@hidden> wrote:
> (i've posted the question already on address@hidden but was toled
> to better use this mailing list)
>
> i've prepared an Debian 7.8.0 image for SPARC64/qemu emulation for C/C++
> development before-real-hardware big-endian/unaligned tests
>
> i've benchmarked compiling of single pugixml.cpp
> (https://github.com/zeux/pugixml/blob/master/src/pugixml.cpp)
>
> qemu-system-sparc64: >180sek
> x64 native : ~ 2sek
>
> so my sparc64 emulation is around 90 times slower then native x64
>
> my system:
>
> using lastest qemu git 2.3.x, with virtio for harddisk/network and qcow2
> image
>
> https://depositfiles.com/files/sj20aqwp0 (~280MB
> press the "regular download" button, wait some seconds, solve the
> chapca, "download file in regular mode by browser"
>
> there is pugi_sparc.txt in the 7z which describes how to start,use and
> what is installed in the image
>
> qemu runs natively under a ubuntu 15.04 (x64), Core i7, 8GB system doing
> nothing but qemu
>

Since the guest  g++ performance problems are caused by MMU emulation,
I think the fastest solution at the moment would be using the user
mode emulation instead of the full system emulation. You can try
mounting your debian disk image with guestfish (or nbd) on your ubuntu
host and chroot into it with statically built qemu-sparc32plus (for
the released Debian/sparc) or statically built qemu-sparc64 (for the
unreleased Debian/sparc64) as described in [1] and [2]. I haven't
tried launching g++, but at least some /bin utilities used to work
with qemu-sparc32plus, at least back in 2011 [2].
NB: I think mixing sparc32plus and sparc64 binaries would not work,
but it should not be a problem, since the userspace of the released
Debian/sparc is pure sparc32plus and the userspace of the unreleased
Debian/sparc64 is pure sparc64.

Artyom

1. https://wiki.debian.org/QemuUserEmulation
2. http://tyom.blogspot.de/2011/07/user-mode-emulation-for-linuxsparc64.html


-- 
Regards,
Artyom Tarasenko

SPARC and PPC PReP under qemu blog: http://tyom.blogspot.com/search/label/qemu