Re: [Qemu-devel] RFC: This project needs a stable branch

[Paul Brook <paul@codesourcery.com>]

On Thursday 22 March 2007 23:57, Julian Seward wrote:
> On Thursday 22 March 2007 23:27, Paul Brook wrote:
> > > Do you mean you're asking me to break up Paul Brook's QOPS tree at
> > > https://nowt.dyndns.org and submit it to mainline?  I can do this
> > > thing, if you really think it would help.
> >
> > If you implement all the missing bits in the process it'll help ;-)
>
> What bits would they be then?

The m68k target is the only one that uses qops for all its code generation. 
Arm is about half-and-half, x86 has the easy bits converted, and the other 
targets still use dyngen pretty much exclusively.

amd64 host support is fairly good, x86 hosts mostly work, and ppc has 
bitrotted a bit.

> FWIW, I snarfed the patch last Sunday and tested it on amd64 host /
> x86 guest, and successfully booted a couple of linux distros.  So it's
> not obviously broken, at least for my mundane host/guest choice.
> It also seemed marginally slower on a big compile in the guest -
> 395.4 host cpu seconds for mainline vs 422.9 with qops.  Is this
> expected?

Yes. The generated code should run at similar speed, but doing the translation 
takes a bit longer. I've been seeing 10-20% slowdown for booting linux.

Paul