Re: [Qemu-devel] Re: [PATCH 08/11] QMP: Port balloon command

[Avi Kivity]

On 06/28/2009 08:51 PM, Blue Swirl wrote:
> On 6/28/09, Filip Navara<address@hidden>  wrote:
>    
> > On Sun, Jun 28, 2009 at 5:52 PM, Avi Kivity<address@hidden>  wrote:
> >   >  It really isn't very complicated, and
> >   >  the thread only got so long because the topic is relatively simple.  Post 
> > an
> >   >  RFC and a mile-long patchset about changing TCG to SSA form, and see how 
> > you
> >   >  get no replies.
> >
> >
> > I wouldn't even dare to push the SSA patch... Mile-long doesn't
> >   describe it precisely enough. Imagine it was applied to all the
> >   targets.
> >      
>
> Is there a speed benefit from using the SSA form?
>    

I'm no compiler expert.  My understanding is that SSA enables 
optimizations, so translation speed would decrease, but generated code 
speed would increase.

Other jits increase optimization effort on long running loops, so if a 
code is run heavily it receives additional attention from the optimizer.


--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.