OK!!
Thank you.
So, I can't get better performances now.
I'm going to integrate some HPC clustering system to speed up UML even
though I don't know if it's the right way... becouse of the I/O
latency time.
Bye.
Flavio
2007/1/23, Blaisorblade <[EMAIL PROTECTED]>:
> On Saturday 20 January 2007 17:39, Flavio wrote:
> > 2007/1/20, Blaisorblade <[EMAIL PROTECTED]>:
> > > I.e. a SMP processor obviously, right?
> >
> > That's right!
> >
> > > UML does not support SMP, so it can use just one processor. This is the
> > > major slowdown case in your comparison.
> > >
> > > Compare make -j2 on the host and on the guest: there will still be some
> > > slowdown, but not such an high one. Possibly on the guest make -j1 could
> > > be better (it would be interesting).
> >
> > host # time make -j2
> > real 1m54.358s
> > user 3m9.300s
> > sys 0m18.910s
>
> Er, it seems that _I_ gave you a wrong suggestion - it is still using both
> processor (though not optimally), so "time make -j1" on _both_ the host and
> the guest is a fairer comparison.
>
> The confusion was born since on a uniprocessor machine it is usually suggested
> to use make -j2. However, make -j2 on a dual core will use both processors.
>
> > guest # time make -j2
> > real 7m37.511s
> > user 2m32.770s
> > sys 0m23.200s
> >
> > guest # time make -j1
> > real 7m41.003s
> > user 2m33.880s
> > sys 0m23.230s
> >
> > :-( '''
> > :
> > > Also, the user time is less on UML. The fact that total time is higher is
> > > probably due to running with -j3 on a uniprocessor machine, and the fact
> > > that the user time is less is probably due to using gcc 3.3 rather than 4
> > > (I seem to recall gcc 4 is slower in compilation than gcc 3).
>
> --
> Inform me of my mistakes, so I can add them to my list!
> Paolo Giarrusso, aka Blaisorblade
> http://www.user-mode-linux.org/~blaisorblade
> Chiacchiera con i tuoi amici in tempo reale!
> http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com
>
>
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